Intermediate changes

commit_hash:88dd3a7e237f5ebeb9b302a0e6866042635fda83

11 files changed, 1210 insertions, 1078 deletions

diff --git a/contrib/python/grpcio/py3/grpc/framework/common/cardinality.py b/contrib/python/grpcio/py3/grpc/framework/common/cardinality.py
index c98735622d7..3d3d4d3427c 100644
--- a/contrib/python/grpcio/py3/grpc/framework/common/cardinality.py
+++ b/contrib/python/grpcio/py3/grpc/framework/common/cardinality.py
@@ -20,7 +20,7 @@ import enum
 class Cardinality(enum.Enum):
     """Describes the streaming semantics of an RPC method."""
 
-    UNARY_UNARY = 'request-unary/response-unary'
-    UNARY_STREAM = 'request-unary/response-streaming'
-    STREAM_UNARY = 'request-streaming/response-unary'
-    STREAM_STREAM = 'request-streaming/response-streaming'
+    UNARY_UNARY = "request-unary/response-unary"
+    UNARY_STREAM = "request-unary/response-streaming"
+    STREAM_UNARY = "request-streaming/response-unary"
+    STREAM_STREAM = "request-streaming/response-streaming"
diff --git a/contrib/python/grpcio/py3/grpc/framework/common/style.py b/contrib/python/grpcio/py3/grpc/framework/common/style.py
index f6138d417ff..10bf5f17697 100644
--- a/contrib/python/grpcio/py3/grpc/framework/common/style.py
+++ b/contrib/python/grpcio/py3/grpc/framework/common/style.py
@@ -20,5 +20,5 @@ import enum
 class Service(enum.Enum):
     """Describes the control flow style of RPC method implementation."""
 
-    INLINE = 'inline'
-    EVENT = 'event'
+    INLINE = "inline"
+    EVENT = "event"
diff --git a/contrib/python/grpcio/py3/grpc/framework/foundation/abandonment.py b/contrib/python/grpcio/py3/grpc/framework/foundation/abandonment.py
index 660ce991c41..c4cb7d5c072 100644
--- a/contrib/python/grpcio/py3/grpc/framework/foundation/abandonment.py
+++ b/contrib/python/grpcio/py3/grpc/framework/foundation/abandonment.py
@@ -17,6 +17,6 @@
 class Abandoned(Exception):
     """Indicates that some computation is being abandoned.
 
-  Abandoning a computation is different than returning a value or raising
-  an exception indicating some operational or programming defect.
-  """
+    Abandoning a computation is different than returning a value or raising
+    an exception indicating some operational or programming defect.
+    """
diff --git a/contrib/python/grpcio/py3/grpc/framework/foundation/callable_util.py b/contrib/python/grpcio/py3/grpc/framework/foundation/callable_util.py
index 0a638eb62e8..b64131b4029 100644
--- a/contrib/python/grpcio/py3/grpc/framework/foundation/callable_util.py
+++ b/contrib/python/grpcio/py3/grpc/framework/foundation/callable_util.py
@@ -25,14 +25,14 @@ _LOGGER = logging.getLogger(__name__)
 class Outcome(ABC):
     """A sum type describing the outcome of some call.
 
-  Attributes:
-    kind: One of Kind.RETURNED or Kind.RAISED respectively indicating that the
-      call returned a value or raised an exception.
-    return_value: The value returned by the call. Must be present if kind is
-      Kind.RETURNED.
-    exception: The exception raised by the call. Must be present if kind is
-      Kind.RAISED.
-  """
+    Attributes:
+      kind: One of Kind.RETURNED or Kind.RAISED respectively indicating that the
+        call returned a value or raised an exception.
+      return_value: The value returned by the call. Must be present if kind is
+        Kind.RETURNED.
+      exception: The exception raised by the call. Must be present if kind is
+        Kind.RAISED.
+    """
 
     @enum.unique
     class Kind(enum.Enum):
@@ -43,15 +43,19 @@ class Outcome(ABC):
 
 
 class _EasyOutcome(
-        collections.namedtuple('_EasyOutcome',
-                               ['kind', 'return_value', 'exception']), Outcome):
+    collections.namedtuple(
+        "_EasyOutcome", ["kind", "return_value", "exception"]
+    ),
+    Outcome,
+):
     """A trivial implementation of Outcome."""
 
 
 def _call_logging_exceptions(behavior, message, *args, **kwargs):
     try:
-        return _EasyOutcome(Outcome.Kind.RETURNED, behavior(*args, **kwargs),
-                            None)
+        return _EasyOutcome(
+            Outcome.Kind.RETURNED, behavior(*args, **kwargs), None
+        )
     except Exception as e:  # pylint: disable=broad-except
         _LOGGER.exception(message)
         return _EasyOutcome(Outcome.Kind.RAISED, None, e)
@@ -60,16 +64,16 @@ def _call_logging_exceptions(behavior, message, *args, **kwargs):
 def with_exceptions_logged(behavior, message):
     """Wraps a callable in a try-except that logs any exceptions it raises.
 
-  Args:
-    behavior: Any callable.
-    message: A string to log if the behavior raises an exception.
+    Args:
+      behavior: Any callable.
+      message: A string to log if the behavior raises an exception.
 
-  Returns:
-    A callable that when executed invokes the given behavior. The returned
-      callable takes the same arguments as the given behavior but returns a
-      future.Outcome describing whether the given behavior returned a value or
-      raised an exception.
-  """
+    Returns:
+      A callable that when executed invokes the given behavior. The returned
+        callable takes the same arguments as the given behavior but returns a
+        future.Outcome describing whether the given behavior returned a value or
+        raised an exception.
+    """
 
     @functools.wraps(behavior)
     def wrapped_behavior(*args, **kwargs):
@@ -81,14 +85,14 @@ def with_exceptions_logged(behavior, message):
 def call_logging_exceptions(behavior, message, *args, **kwargs):
     """Calls a behavior in a try-except that logs any exceptions it raises.
 
-  Args:
-    behavior: Any callable.
-    message: A string to log if the behavior raises an exception.
-    *args: Positional arguments to pass to the given behavior.
-    **kwargs: Keyword arguments to pass to the given behavior.
+    Args:
+      behavior: Any callable.
+      message: A string to log if the behavior raises an exception.
+      *args: Positional arguments to pass to the given behavior.
+      **kwargs: Keyword arguments to pass to the given behavior.
 
-  Returns:
-    An Outcome describing whether the given behavior returned a value or raised
-      an exception.
-  """
+    Returns:
+      An Outcome describing whether the given behavior returned a value or raised
+        an exception.
+    """
     return _call_logging_exceptions(behavior, message, *args, **kwargs)
diff --git a/contrib/python/grpcio/py3/grpc/framework/foundation/future.py b/contrib/python/grpcio/py3/grpc/framework/foundation/future.py
index c7996aa8a56..73b0d0bdbe1 100644
--- a/contrib/python/grpcio/py3/grpc/framework/foundation/future.py
+++ b/contrib/python/grpcio/py3/grpc/framework/foundation/future.py
@@ -45,9 +45,9 @@ class CancelledError(Exception):
 class Future(abc.ABC):
     """A representation of a computation in another control flow.
 
-  Computations represented by a Future may be yet to be begun, may be ongoing,
-  or may have already completed.
-  """
+    Computations represented by a Future may be yet to be begun, may be ongoing,
+    or may have already completed.
+    """
 
     # NOTE(nathaniel): This isn't the return type that I would want to have if it
     # were up to me. Were this interface being written from scratch, the return
@@ -63,17 +63,17 @@ class Future(abc.ABC):
     def cancel(self):
         """Attempts to cancel the computation.
 
-    This method does not block.
-
-    Returns:
-      True if the computation has not yet begun, will not be allowed to take
-        place, and determination of both was possible without blocking. False
-        under all other circumstances including but not limited to the
-        computation's already having begun, the computation's already having
-        finished, and the computation's having been scheduled for execution on a
-        remote system for which a determination of whether or not it commenced
-        before being cancelled cannot be made without blocking.
-    """
+        This method does not block.
+
+        Returns:
+          True if the computation has not yet begun, will not be allowed to take
+            place, and determination of both was possible without blocking. False
+            under all other circumstances including but not limited to the
+            computation's already having begun, the computation's already having
+            finished, and the computation's having been scheduled for execution on a
+            remote system for which a determination of whether or not it commenced
+            before being cancelled cannot be made without blocking.
+        """
         raise NotImplementedError()
 
     # NOTE(nathaniel): Here too this isn't the return type that I'd want this
@@ -94,27 +94,27 @@ class Future(abc.ABC):
     def cancelled(self):
         """Describes whether the computation was cancelled.
 
-    This method does not block.
+        This method does not block.
 
-    Returns:
-      True if the computation was cancelled any time before its result became
-        immediately available. False under all other circumstances including but
-        not limited to this object's cancel method not having been called and
-        the computation's result having become immediately available.
-    """
+        Returns:
+          True if the computation was cancelled any time before its result became
+            immediately available. False under all other circumstances including but
+            not limited to this object's cancel method not having been called and
+            the computation's result having become immediately available.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def running(self):
         """Describes whether the computation is taking place.
 
-    This method does not block.
+        This method does not block.
 
-    Returns:
-      True if the computation is scheduled to take place in the future or is
-        taking place now, or False if the computation took place in the past or
-        was cancelled.
-    """
+        Returns:
+          True if the computation is scheduled to take place in the future or is
+            taking place now, or False if the computation took place in the past or
+            was cancelled.
+        """
         raise NotImplementedError()
 
     # NOTE(nathaniel): These aren't quite the semantics I'd like here either. I
@@ -125,95 +125,95 @@ class Future(abc.ABC):
     def done(self):
         """Describes whether the computation has taken place.
 
-    This method does not block.
+        This method does not block.
 
-    Returns:
-      True if the computation is known to have either completed or have been
-        unscheduled or interrupted. False if the computation may possibly be
-        executing or scheduled to execute later.
-    """
+        Returns:
+          True if the computation is known to have either completed or have been
+            unscheduled or interrupted. False if the computation may possibly be
+            executing or scheduled to execute later.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def result(self, timeout=None):
         """Accesses the outcome of the computation or raises its exception.
 
-    This method may return immediately or may block.
+        This method may return immediately or may block.
 
-    Args:
-      timeout: The length of time in seconds to wait for the computation to
-        finish or be cancelled, or None if this method should block until the
-        computation has finished or is cancelled no matter how long that takes.
+        Args:
+          timeout: The length of time in seconds to wait for the computation to
+            finish or be cancelled, or None if this method should block until the
+            computation has finished or is cancelled no matter how long that takes.
 
-    Returns:
-      The return value of the computation.
+        Returns:
+          The return value of the computation.
 
-    Raises:
-      TimeoutError: If a timeout value is passed and the computation does not
-        terminate within the allotted time.
-      CancelledError: If the computation was cancelled.
-      Exception: If the computation raised an exception, this call will raise
-        the same exception.
-    """
+        Raises:
+          TimeoutError: If a timeout value is passed and the computation does not
+            terminate within the allotted time.
+          CancelledError: If the computation was cancelled.
+          Exception: If the computation raised an exception, this call will raise
+            the same exception.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def exception(self, timeout=None):
         """Return the exception raised by the computation.
 
-    This method may return immediately or may block.
+        This method may return immediately or may block.
 
-    Args:
-      timeout: The length of time in seconds to wait for the computation to
-        terminate or be cancelled, or None if this method should block until
-        the computation is terminated or is cancelled no matter how long that
-        takes.
+        Args:
+          timeout: The length of time in seconds to wait for the computation to
+            terminate or be cancelled, or None if this method should block until
+            the computation is terminated or is cancelled no matter how long that
+            takes.
 
-    Returns:
-      The exception raised by the computation, or None if the computation did
-        not raise an exception.
+        Returns:
+          The exception raised by the computation, or None if the computation did
+            not raise an exception.
 
-    Raises:
-      TimeoutError: If a timeout value is passed and the computation does not
-        terminate within the allotted time.
-      CancelledError: If the computation was cancelled.
-    """
+        Raises:
+          TimeoutError: If a timeout value is passed and the computation does not
+            terminate within the allotted time.
+          CancelledError: If the computation was cancelled.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def traceback(self, timeout=None):
         """Access the traceback of the exception raised by the computation.
 
-    This method may return immediately or may block.
+        This method may return immediately or may block.
 
-    Args:
-      timeout: The length of time in seconds to wait for the computation to
-        terminate or be cancelled, or None if this method should block until
-        the computation is terminated or is cancelled no matter how long that
-        takes.
+        Args:
+          timeout: The length of time in seconds to wait for the computation to
+            terminate or be cancelled, or None if this method should block until
+            the computation is terminated or is cancelled no matter how long that
+            takes.
 
-    Returns:
-      The traceback of the exception raised by the computation, or None if the
-        computation did not raise an exception.
+        Returns:
+          The traceback of the exception raised by the computation, or None if the
+            computation did not raise an exception.
 
-    Raises:
-      TimeoutError: If a timeout value is passed and the computation does not
-        terminate within the allotted time.
-      CancelledError: If the computation was cancelled.
-    """
+        Raises:
+          TimeoutError: If a timeout value is passed and the computation does not
+            terminate within the allotted time.
+          CancelledError: If the computation was cancelled.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def add_done_callback(self, fn):
         """Adds a function to be called at completion of the computation.
 
-    The callback will be passed this Future object describing the outcome of
-    the computation.
+        The callback will be passed this Future object describing the outcome of
+        the computation.
 
-    If the computation has already completed, the callback will be called
-    immediately.
+        If the computation has already completed, the callback will be called
+        immediately.
 
-    Args:
-      fn: A callable taking this Future object as its single parameter.
-    """
+        Args:
+          fn: A callable taking this Future object as its single parameter.
+        """
         raise NotImplementedError()
diff --git a/contrib/python/grpcio/py3/grpc/framework/foundation/logging_pool.py b/contrib/python/grpcio/py3/grpc/framework/foundation/logging_pool.py
index 53d2cd00825..a4e140f174d 100644
--- a/contrib/python/grpcio/py3/grpc/framework/foundation/logging_pool.py
+++ b/contrib/python/grpcio/py3/grpc/framework/foundation/logging_pool.py
@@ -27,8 +27,9 @@ def _wrap(behavior):
             return behavior(*args, **kwargs)
         except Exception:
             _LOGGER.exception(
-                'Unexpected exception from %s executed in logging pool!',
-                behavior)
+                "Unexpected exception from %s executed in logging pool!",
+                behavior,
+            )
             raise
 
     return _wrapping
@@ -50,9 +51,9 @@ class _LoggingPool(object):
         return self._backing_pool.submit(_wrap(fn), *args, **kwargs)
 
     def map(self, func, *iterables, **kwargs):
-        return self._backing_pool.map(_wrap(func),
-                                      *iterables,
-                                      timeout=kwargs.get('timeout', None))
+        return self._backing_pool.map(
+            _wrap(func), *iterables, timeout=kwargs.get("timeout", None)
+        )
 
     def shutdown(self, wait=True):
         self._backing_pool.shutdown(wait=wait)
@@ -61,11 +62,11 @@ class _LoggingPool(object):
 def pool(max_workers):
     """Creates a thread pool that logs exceptions raised by the tasks within it.
 
-  Args:
-    max_workers: The maximum number of worker threads to allow the pool.
+    Args:
+      max_workers: The maximum number of worker threads to allow the pool.
 
-  Returns:
-    A futures.ThreadPoolExecutor-compatible thread pool that logs exceptions
-      raised by the tasks executed within it.
-  """
+    Returns:
+      A futures.ThreadPoolExecutor-compatible thread pool that logs exceptions
+        raised by the tasks executed within it.
+    """
     return _LoggingPool(futures.ThreadPoolExecutor(max_workers))
diff --git a/contrib/python/grpcio/py3/grpc/framework/foundation/stream.py b/contrib/python/grpcio/py3/grpc/framework/foundation/stream.py
index 150a22435ee..70ca1d91575 100644
--- a/contrib/python/grpcio/py3/grpc/framework/foundation/stream.py
+++ b/contrib/python/grpcio/py3/grpc/framework/foundation/stream.py
@@ -23,9 +23,9 @@ class Consumer(abc.ABC):
     def consume(self, value):
         """Accepts a value.
 
-    Args:
-      value: Any value accepted by this Consumer.
-    """
+        Args:
+          value: Any value accepted by this Consumer.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
@@ -37,7 +37,7 @@ class Consumer(abc.ABC):
     def consume_and_terminate(self, value):
         """Supplies a value and signals that no more values will be supplied.
 
-    Args:
-      value: Any value accepted by this Consumer.
-    """
+        Args:
+          value: Any value accepted by this Consumer.
+        """
         raise NotImplementedError()
diff --git a/contrib/python/grpcio/py3/grpc/framework/interfaces/base/base.py b/contrib/python/grpcio/py3/grpc/framework/interfaces/base/base.py
index 8caee325c2c..d1c0b079116 100644
--- a/contrib/python/grpcio/py3/grpc/framework/interfaces/base/base.py
+++ b/contrib/python/grpcio/py3/grpc/framework/interfaces/base/base.py
@@ -56,37 +56,37 @@ class NoSuchMethodError(Exception):
 class Outcome(object):
     """The outcome of an operation.
 
-  Attributes:
-    kind: A Kind value coarsely identifying how the operation terminated.
-    code: An application-specific code value or None if no such value was
-      provided.
-    details: An application-specific details value or None if no such value was
-      provided.
-  """
+    Attributes:
+      kind: A Kind value coarsely identifying how the operation terminated.
+      code: An application-specific code value or None if no such value was
+        provided.
+      details: An application-specific details value or None if no such value was
+        provided.
+    """
 
     @enum.unique
     class Kind(enum.Enum):
         """Ways in which an operation can terminate."""
 
-        COMPLETED = 'completed'
-        CANCELLED = 'cancelled'
-        EXPIRED = 'expired'
-        LOCAL_SHUTDOWN = 'local shutdown'
-        REMOTE_SHUTDOWN = 'remote shutdown'
-        RECEPTION_FAILURE = 'reception failure'
-        TRANSMISSION_FAILURE = 'transmission failure'
-        LOCAL_FAILURE = 'local failure'
-        REMOTE_FAILURE = 'remote failure'
+        COMPLETED = "completed"
+        CANCELLED = "cancelled"
+        EXPIRED = "expired"
+        LOCAL_SHUTDOWN = "local shutdown"
+        REMOTE_SHUTDOWN = "remote shutdown"
+        RECEPTION_FAILURE = "reception failure"
+        TRANSMISSION_FAILURE = "transmission failure"
+        LOCAL_FAILURE = "local failure"
+        REMOTE_FAILURE = "remote failure"
 
 
 class Completion(abc.ABC):
     """An aggregate of the values exchanged upon operation completion.
 
-  Attributes:
-    terminal_metadata: A terminal metadata value for the operaton.
-    code: A code value for the operation.
-    message: A message value for the operation.
-  """
+    Attributes:
+      terminal_metadata: A terminal metadata value for the operaton.
+      code: A code value for the operation.
+      message: A message value for the operation.
+    """
 
 
 class OperationContext(abc.ABC):
@@ -96,37 +96,37 @@ class OperationContext(abc.ABC):
     def outcome(self):
         """Indicates the operation's outcome (or that the operation is ongoing).
 
-    Returns:
-      None if the operation is still active or the Outcome value for the
-        operation if it has terminated.
-    """
+        Returns:
+          None if the operation is still active or the Outcome value for the
+            operation if it has terminated.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def add_termination_callback(self, callback):
         """Adds a function to be called upon operation termination.
 
-    Args:
-      callback: A callable to be passed an Outcome value on operation
-        termination.
-
-    Returns:
-      None if the operation has not yet terminated and the passed callback will
-        later be called when it does terminate, or if the operation has already
-        terminated an Outcome value describing the operation termination and the
-        passed callback will not be called as a result of this method call.
-    """
+        Args:
+          callback: A callable to be passed an Outcome value on operation
+            termination.
+
+        Returns:
+          None if the operation has not yet terminated and the passed callback will
+            later be called when it does terminate, or if the operation has already
+            terminated an Outcome value describing the operation termination and the
+            passed callback will not be called as a result of this method call.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def time_remaining(self):
         """Describes the length of allowed time remaining for the operation.
 
-    Returns:
-      A nonnegative float indicating the length of allowed time in seconds
-      remaining for the operation to complete before it is considered to have
-      timed out. Zero is returned if the operation has terminated.
-    """
+        Returns:
+          A nonnegative float indicating the length of allowed time in seconds
+          remaining for the operation to complete before it is considered to have
+          timed out. Zero is returned if the operation has terminated.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
@@ -138,9 +138,9 @@ class OperationContext(abc.ABC):
     def fail(self, exception):
         """Indicates that the operation has failed.
 
-    Args:
-      exception: An exception germane to the operation failure. May be None.
-    """
+        Args:
+          exception: An exception germane to the operation failure. May be None.
+        """
         raise NotImplementedError()
 
 
@@ -148,23 +148,25 @@ class Operator(abc.ABC):
     """An interface through which to participate in an operation."""
 
     @abc.abstractmethod
-    def advance(self,
-                initial_metadata=None,
-                payload=None,
-                completion=None,
-                allowance=None):
+    def advance(
+        self,
+        initial_metadata=None,
+        payload=None,
+        completion=None,
+        allowance=None,
+    ):
         """Progresses the operation.
 
-    Args:
-      initial_metadata: An initial metadata value. Only one may ever be
-        communicated in each direction for an operation, and they must be
-        communicated no later than either the first payload or the completion.
-      payload: A payload value.
-      completion: A Completion value. May only ever be non-None once in either
-        direction, and no payloads may be passed after it has been communicated.
-      allowance: A positive integer communicating the number of additional
-        payloads allowed to be passed by the remote side of the operation.
-    """
+        Args:
+          initial_metadata: An initial metadata value. Only one may ever be
+            communicated in each direction for an operation, and they must be
+            communicated no later than either the first payload or the completion.
+          payload: A payload value.
+          completion: A Completion value. May only ever be non-None once in either
+            direction, and no payloads may be passed after it has been communicated.
+          allowance: A positive integer communicating the number of additional
+            payloads allowed to be passed by the remote side of the operation.
+        """
         raise NotImplementedError()
 
 
@@ -175,37 +177,36 @@ class ProtocolReceiver(abc.ABC):
     def context(self, protocol_context):
         """Accepts the protocol context object for the operation.
 
-    Args:
-      protocol_context: The protocol context object for the operation.
-    """
+        Args:
+          protocol_context: The protocol context object for the operation.
+        """
         raise NotImplementedError()
 
 
 class Subscription(abc.ABC):
     """Describes customer code's interest in values from the other side.
 
-  Attributes:
-    kind: A Kind value describing the overall kind of this value.
-    termination_callback: A callable to be passed the Outcome associated with
-      the operation after it has terminated. Must be non-None if kind is
-      Kind.TERMINATION_ONLY. Must be None otherwise.
-    allowance: A callable behavior that accepts positive integers representing
-      the number of additional payloads allowed to be passed to the other side
-      of the operation. Must be None if kind is Kind.FULL. Must not be None
-      otherwise.
-    operator: An Operator to be passed values from the other side of the
-      operation. Must be non-None if kind is Kind.FULL. Must be None otherwise.
-    protocol_receiver: A ProtocolReceiver to be passed protocol objects as they
-      become available during the operation. Must be non-None if kind is
-      Kind.FULL.
-  """
+    Attributes:
+      kind: A Kind value describing the overall kind of this value.
+      termination_callback: A callable to be passed the Outcome associated with
+        the operation after it has terminated. Must be non-None if kind is
+        Kind.TERMINATION_ONLY. Must be None otherwise.
+      allowance: A callable behavior that accepts positive integers representing
+        the number of additional payloads allowed to be passed to the other side
+        of the operation. Must be None if kind is Kind.FULL. Must not be None
+        otherwise.
+      operator: An Operator to be passed values from the other side of the
+        operation. Must be non-None if kind is Kind.FULL. Must be None otherwise.
+      protocol_receiver: A ProtocolReceiver to be passed protocol objects as they
+        become available during the operation. Must be non-None if kind is
+        Kind.FULL.
+    """
 
     @enum.unique
     class Kind(enum.Enum):
-
-        NONE = 'none'
-        TERMINATION_ONLY = 'termination only'
-        FULL = 'full'
+        NONE = "none"
+        TERMINATION_ONLY = "termination only"
+        FULL = "full"
 
 
 class Servicer(abc.ABC):
@@ -215,24 +216,24 @@ class Servicer(abc.ABC):
     def service(self, group, method, context, output_operator):
         """Services an operation.
 
-    Args:
-      group: The group identifier of the operation to be serviced.
-      method: The method identifier of the operation to be serviced.
-      context: An OperationContext object affording contextual information and
-        actions.
-      output_operator: An Operator that will accept output values of the
-        operation.
-
-    Returns:
-      A Subscription via which this object may or may not accept more values of
-        the operation.
-
-    Raises:
-      NoSuchMethodError: If this Servicer does not handle operations with the
-        given group and method.
-      abandonment.Abandoned: If the operation has been aborted and there no
-        longer is any reason to service the operation.
-    """
+        Args:
+          group: The group identifier of the operation to be serviced.
+          method: The method identifier of the operation to be serviced.
+          context: An OperationContext object affording contextual information and
+            actions.
+          output_operator: An Operator that will accept output values of the
+            operation.
+
+        Returns:
+          A Subscription via which this object may or may not accept more values of
+            the operation.
+
+        Raises:
+          NoSuchMethodError: If this Servicer does not handle operations with the
+            given group and method.
+          abandonment.Abandoned: If the operation has been aborted and there no
+            longer is any reason to service the operation.
+        """
         raise NotImplementedError()
 
 
@@ -248,78 +249,80 @@ class End(abc.ABC):
     def stop(self, grace):
         """Stops this object's service of operations.
 
-    This object will refuse service of new operations as soon as this method is
-    called but operations under way at the time of the call may be given a
-    grace period during which they are allowed to finish.
-
-    Args:
-      grace: A duration of time in seconds to allow ongoing operations to
-        terminate before being forcefully terminated by the stopping of this
-        End. May be zero to terminate all ongoing operations and immediately
-        stop.
-
-    Returns:
-      A threading.Event that will be set to indicate all operations having
-        terminated and this End having completely stopped. The returned event
-        may not be set until after the full grace period (if some ongoing
-        operation continues for the full length of the period) or it may be set
-        much sooner (if for example this End had no operations in progress at
-        the time its stop method was called).
-    """
+        This object will refuse service of new operations as soon as this method is
+        called but operations under way at the time of the call may be given a
+        grace period during which they are allowed to finish.
+
+        Args:
+          grace: A duration of time in seconds to allow ongoing operations to
+            terminate before being forcefully terminated by the stopping of this
+            End. May be zero to terminate all ongoing operations and immediately
+            stop.
+
+        Returns:
+          A threading.Event that will be set to indicate all operations having
+            terminated and this End having completely stopped. The returned event
+            may not be set until after the full grace period (if some ongoing
+            operation continues for the full length of the period) or it may be set
+            much sooner (if for example this End had no operations in progress at
+            the time its stop method was called).
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def operate(self,
-                group,
-                method,
-                subscription,
-                timeout,
-                initial_metadata=None,
-                payload=None,
-                completion=None,
-                protocol_options=None):
+    def operate(
+        self,
+        group,
+        method,
+        subscription,
+        timeout,
+        initial_metadata=None,
+        payload=None,
+        completion=None,
+        protocol_options=None,
+    ):
         """Commences an operation.
 
-    Args:
-      group: The group identifier of the invoked operation.
-      method: The method identifier of the invoked operation.
-      subscription: A Subscription to which the results of the operation will be
-        passed.
-      timeout: A length of time in seconds to allow for the operation.
-      initial_metadata: An initial metadata value to be sent to the other side
-        of the operation. May be None if the initial metadata will be later
-        passed via the returned operator or if there will be no initial metadata
-        passed at all.
-      payload: An initial payload for the operation.
-      completion: A Completion value indicating the end of transmission to the
-        other side of the operation.
-      protocol_options: A value specified by the provider of a Base interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A pair of objects affording information about the operation and action
-        continuing the operation. The first element of the returned pair is an
-        OperationContext for the operation and the second element of the
-        returned pair is an Operator to which operation values not passed in
-        this call should later be passed.
-    """
+        Args:
+          group: The group identifier of the invoked operation.
+          method: The method identifier of the invoked operation.
+          subscription: A Subscription to which the results of the operation will be
+            passed.
+          timeout: A length of time in seconds to allow for the operation.
+          initial_metadata: An initial metadata value to be sent to the other side
+            of the operation. May be None if the initial metadata will be later
+            passed via the returned operator or if there will be no initial metadata
+            passed at all.
+          payload: An initial payload for the operation.
+          completion: A Completion value indicating the end of transmission to the
+            other side of the operation.
+          protocol_options: A value specified by the provider of a Base interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A pair of objects affording information about the operation and action
+            continuing the operation. The first element of the returned pair is an
+            OperationContext for the operation and the second element of the
+            returned pair is an Operator to which operation values not passed in
+            this call should later be passed.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def operation_stats(self):
         """Reports the number of terminated operations broken down by outcome.
 
-    Returns:
-      A dictionary from Outcome.Kind value to an integer identifying the number
-        of operations that terminated with that outcome kind.
-    """
+        Returns:
+          A dictionary from Outcome.Kind value to an integer identifying the number
+            of operations that terminated with that outcome kind.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def add_idle_action(self, action):
         """Adds an action to be called when this End has no ongoing operations.
 
-    Args:
-      action: A callable that accepts no arguments.
-    """
+        Args:
+          action: A callable that accepts no arguments.
+        """
         raise NotImplementedError()
diff --git a/contrib/python/grpcio/py3/grpc/framework/interfaces/base/utilities.py b/contrib/python/grpcio/py3/grpc/framework/interfaces/base/utilities.py
index 281db62b5d4..d188339b1eb 100644
--- a/contrib/python/grpcio/py3/grpc/framework/interfaces/base/utilities.py
+++ b/contrib/python/grpcio/py3/grpc/framework/interfaces/base/utilities.py
@@ -18,54 +18,66 @@ import collections
 from grpc.framework.interfaces.base import base
 
 
-class _Completion(base.Completion,
-                  collections.namedtuple('_Completion', (
-                      'terminal_metadata',
-                      'code',
-                      'message',
-                  ))):
+class _Completion(
+    base.Completion,
+    collections.namedtuple(
+        "_Completion",
+        (
+            "terminal_metadata",
+            "code",
+            "message",
+        ),
+    ),
+):
     """A trivial implementation of base.Completion."""
 
 
-class _Subscription(base.Subscription,
-                    collections.namedtuple('_Subscription', (
-                        'kind',
-                        'termination_callback',
-                        'allowance',
-                        'operator',
-                        'protocol_receiver',
-                    ))):
+class _Subscription(
+    base.Subscription,
+    collections.namedtuple(
+        "_Subscription",
+        (
+            "kind",
+            "termination_callback",
+            "allowance",
+            "operator",
+            "protocol_receiver",
+        ),
+    ),
+):
     """A trivial implementation of base.Subscription."""
 
 
-_NONE_SUBSCRIPTION = _Subscription(base.Subscription.Kind.NONE, None, None,
-                                   None, None)
+_NONE_SUBSCRIPTION = _Subscription(
+    base.Subscription.Kind.NONE, None, None, None, None
+)
 
 
 def completion(terminal_metadata, code, message):
     """Creates a base.Completion aggregating the given operation values.
 
-  Args:
-    terminal_metadata: A terminal metadata value for an operaton.
-    code: A code value for an operation.
-    message: A message value for an operation.
+    Args:
+      terminal_metadata: A terminal metadata value for an operaton.
+      code: A code value for an operation.
+      message: A message value for an operation.
 
-  Returns:
-    A base.Completion aggregating the given operation values.
-  """
+    Returns:
+      A base.Completion aggregating the given operation values.
+    """
     return _Completion(terminal_metadata, code, message)
 
 
 def full_subscription(operator, protocol_receiver):
     """Creates a "full" base.Subscription for the given base.Operator.
 
-  Args:
-    operator: A base.Operator to be used in an operation.
-    protocol_receiver: A base.ProtocolReceiver to be used in an operation.
-
-  Returns:
-    A base.Subscription of kind base.Subscription.Kind.FULL wrapping the given
-      base.Operator and base.ProtocolReceiver.
-  """
-    return _Subscription(base.Subscription.Kind.FULL, None, None, operator,
-                         protocol_receiver)
+    Args:
+      operator: A base.Operator to be used in an operation.
+      protocol_receiver: A base.ProtocolReceiver to be used in an operation.
+
+    Returns:
+      A base.Subscription of kind base.Subscription.Kind.FULL wrapping the given
+        base.Operator and base.ProtocolReceiver.
+    """
+    return _Subscription(
+        base.Subscription.Kind.FULL, None, None, operator, protocol_receiver
+    )
diff --git a/contrib/python/grpcio/py3/grpc/framework/interfaces/face/face.py b/contrib/python/grpcio/py3/grpc/framework/interfaces/face/face.py
index ed0de6a7de2..9239fcc9eb9 100644
--- a/contrib/python/grpcio/py3/grpc/framework/interfaces/face/face.py
+++ b/contrib/python/grpcio/py3/grpc/framework/interfaces/face/face.py
@@ -30,62 +30,66 @@ from grpc.framework.foundation import stream  # pylint: disable=unused-import
 class NoSuchMethodError(Exception):
     """Raised by customer code to indicate an unrecognized method.
 
-  Attributes:
-    group: The group of the unrecognized method.
-    name: The name of the unrecognized method.
-  """
+    Attributes:
+      group: The group of the unrecognized method.
+      name: The name of the unrecognized method.
+    """
 
     def __init__(self, group, method):
         """Constructor.
 
-    Args:
-      group: The group identifier of the unrecognized RPC name.
-      method: The method identifier of the unrecognized RPC name.
-    """
+        Args:
+          group: The group identifier of the unrecognized RPC name.
+          method: The method identifier of the unrecognized RPC name.
+        """
         super(NoSuchMethodError, self).__init__()
         self.group = group
         self.method = method
 
     def __repr__(self):
-        return 'face.NoSuchMethodError(%s, %s)' % (
+        return "face.NoSuchMethodError(%s, %s)" % (
             self.group,
             self.method,
         )
 
 
 class Abortion(
-        collections.namedtuple('Abortion', (
-            'kind',
-            'initial_metadata',
-            'terminal_metadata',
-            'code',
-            'details',
-        ))):
+    collections.namedtuple(
+        "Abortion",
+        (
+            "kind",
+            "initial_metadata",
+            "terminal_metadata",
+            "code",
+            "details",
+        ),
+    )
+):
     """A value describing RPC abortion.
 
-  Attributes:
-    kind: A Kind value identifying how the RPC failed.
-    initial_metadata: The initial metadata from the other side of the RPC or
-      None if no initial metadata value was received.
-    terminal_metadata: The terminal metadata from the other side of the RPC or
-      None if no terminal metadata value was received.
-    code: The code value from the other side of the RPC or None if no code value
-      was received.
-    details: The details value from the other side of the RPC or None if no
-      details value was received.
-  """
+    Attributes:
+      kind: A Kind value identifying how the RPC failed.
+      initial_metadata: The initial metadata from the other side of the RPC or
+        None if no initial metadata value was received.
+      terminal_metadata: The terminal metadata from the other side of the RPC or
+        None if no terminal metadata value was received.
+      code: The code value from the other side of the RPC or None if no code value
+        was received.
+      details: The details value from the other side of the RPC or None if no
+        details value was received.
+    """
 
     @enum.unique
     class Kind(enum.Enum):
         """Types of RPC abortion."""
 
-        CANCELLED = 'cancelled'
-        EXPIRED = 'expired'
-        LOCAL_SHUTDOWN = 'local shutdown'
-        REMOTE_SHUTDOWN = 'remote shutdown'
-        NETWORK_FAILURE = 'network failure'
-        LOCAL_FAILURE = 'local failure'
-        REMOTE_FAILURE = 'remote failure'
+        CANCELLED = "cancelled"
+        EXPIRED = "expired"
+        LOCAL_SHUTDOWN = "local shutdown"
+        REMOTE_SHUTDOWN = "remote shutdown"
+        NETWORK_FAILURE = "network failure"
+        LOCAL_FAILURE = "local failure"
+        REMOTE_FAILURE = "remote failure"
 
 
 class AbortionError(Exception, metaclass=abc.ABCMeta):
@@ -99,7 +103,7 @@ class AbortionError(Exception, metaclass=abc.ABCMeta):
       was received.
     details: The details value from the other side of the RPC or None if no
       details value was received.
-  """
+    """
 
     def __init__(self, initial_metadata, terminal_metadata, code, details):
         super(AbortionError, self).__init__()
@@ -109,8 +113,11 @@ class AbortionError(Exception, metaclass=abc.ABCMeta):
         self.details = details
 
     def __str__(self):
-        return '%s(code=%s, details="%s")' % (self.__class__.__name__,
-                                              self.code, self.details)
+        return '%s(code=%s, details="%s")' % (
+            self.__class__.__name__,
+            self.code,
+            self.details,
+        )
 
 
 class CancellationError(AbortionError):
@@ -153,39 +160,39 @@ class RpcContext(abc.ABC):
     def time_remaining(self):
         """Describes the length of allowed time remaining for the RPC.
 
-    Returns:
-      A nonnegative float indicating the length of allowed time in seconds
-      remaining for the RPC to complete before it is considered to have timed
-      out.
-    """
+        Returns:
+          A nonnegative float indicating the length of allowed time in seconds
+          remaining for the RPC to complete before it is considered to have timed
+          out.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def add_abortion_callback(self, abortion_callback):
         """Registers a callback to be called if the RPC is aborted.
 
-    Args:
-      abortion_callback: A callable to be called and passed an Abortion value
-        in the event of RPC abortion.
-    """
+        Args:
+          abortion_callback: A callable to be called and passed an Abortion value
+            in the event of RPC abortion.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def cancel(self):
         """Cancels the RPC.
 
-    Idempotent and has no effect if the RPC has already terminated.
-    """
+        Idempotent and has no effect if the RPC has already terminated.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def protocol_context(self):
         """Accesses a custom object specified by an implementation provider.
 
-    Returns:
-      A value specified by the provider of a Face interface implementation
-        affording custom state and behavior.
-    """
+        Returns:
+          A value specified by the provider of a Face interface implementation
+            affording custom state and behavior.
+        """
         raise NotImplementedError()
 
 
@@ -196,52 +203,52 @@ class Call(RpcContext, metaclass=abc.ABCMeta):
     def initial_metadata(self):
         """Accesses the initial metadata from the service-side of the RPC.
 
-    This method blocks until the value is available or is known not to have been
-    emitted from the service-side of the RPC.
+        This method blocks until the value is available or is known not to have been
+        emitted from the service-side of the RPC.
 
-    Returns:
-      The initial metadata object emitted by the service-side of the RPC, or
-        None if there was no such value.
-    """
+        Returns:
+          The initial metadata object emitted by the service-side of the RPC, or
+            None if there was no such value.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def terminal_metadata(self):
         """Accesses the terminal metadata from the service-side of the RPC.
 
-    This method blocks until the value is available or is known not to have been
-    emitted from the service-side of the RPC.
+        This method blocks until the value is available or is known not to have been
+        emitted from the service-side of the RPC.
 
-    Returns:
-      The terminal metadata object emitted by the service-side of the RPC, or
-        None if there was no such value.
-    """
+        Returns:
+          The terminal metadata object emitted by the service-side of the RPC, or
+            None if there was no such value.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def code(self):
         """Accesses the code emitted by the service-side of the RPC.
 
-    This method blocks until the value is available or is known not to have been
-    emitted from the service-side of the RPC.
+        This method blocks until the value is available or is known not to have been
+        emitted from the service-side of the RPC.
 
-    Returns:
-      The code object emitted by the service-side of the RPC, or None if there
-        was no such value.
-    """
+        Returns:
+          The code object emitted by the service-side of the RPC, or None if there
+            was no such value.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def details(self):
         """Accesses the details value emitted by the service-side of the RPC.
 
-    This method blocks until the value is available or is known not to have been
-    emitted from the service-side of the RPC.
+        This method blocks until the value is available or is known not to have been
+        emitted from the service-side of the RPC.
 
-    Returns:
-      The details value emitted by the service-side of the RPC, or None if there
-        was no such value.
-    """
+        Returns:
+          The details value emitted by the service-side of the RPC, or None if there
+            was no such value.
+        """
         raise NotImplementedError()
 
 
@@ -252,65 +259,65 @@ class ServicerContext(RpcContext, metaclass=abc.ABCMeta):
     def invocation_metadata(self):
         """Accesses the metadata from the invocation-side of the RPC.
 
-    This method blocks until the value is available or is known not to have been
-    emitted from the invocation-side of the RPC.
+        This method blocks until the value is available or is known not to have been
+        emitted from the invocation-side of the RPC.
 
-    Returns:
-      The metadata object emitted by the invocation-side of the RPC, or None if
-        there was no such value.
-    """
+        Returns:
+          The metadata object emitted by the invocation-side of the RPC, or None if
+            there was no such value.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def initial_metadata(self, initial_metadata):
         """Accepts the service-side initial metadata value of the RPC.
 
-    This method need not be called by method implementations if they have no
-    service-side initial metadata to transmit.
+        This method need not be called by method implementations if they have no
+        service-side initial metadata to transmit.
 
-    Args:
-      initial_metadata: The service-side initial metadata value of the RPC to
-        be transmitted to the invocation side of the RPC.
-    """
+        Args:
+          initial_metadata: The service-side initial metadata value of the RPC to
+            be transmitted to the invocation side of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def terminal_metadata(self, terminal_metadata):
         """Accepts the service-side terminal metadata value of the RPC.
 
-    This method need not be called by method implementations if they have no
-    service-side terminal metadata to transmit.
+        This method need not be called by method implementations if they have no
+        service-side terminal metadata to transmit.
 
-    Args:
-      terminal_metadata: The service-side terminal metadata value of the RPC to
-        be transmitted to the invocation side of the RPC.
-    """
+        Args:
+          terminal_metadata: The service-side terminal metadata value of the RPC to
+            be transmitted to the invocation side of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def code(self, code):
         """Accepts the service-side code of the RPC.
 
-    This method need not be called by method implementations if they have no
-    code to transmit.
+        This method need not be called by method implementations if they have no
+        code to transmit.
 
-    Args:
-      code: The code of the RPC to be transmitted to the invocation side of the
-        RPC.
-    """
+        Args:
+          code: The code of the RPC to be transmitted to the invocation side of the
+            RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def details(self, details):
         """Accepts the service-side details of the RPC.
 
-    This method need not be called by method implementations if they have no
-    service-side details to transmit.
+        This method need not be called by method implementations if they have no
+        service-side details to transmit.
 
-    Args:
-      details: The service-side details value of the RPC to be transmitted to
-        the invocation side of the RPC.
-    """
+        Args:
+          details: The service-side details value of the RPC to be transmitted to
+            the invocation side of the RPC.
+        """
         raise NotImplementedError()
 
 
@@ -321,31 +328,31 @@ class ResponseReceiver(abc.ABC):
     def initial_metadata(self, initial_metadata):
         """Receives the initial metadata from the service-side of the RPC.
 
-    Args:
-      initial_metadata: The initial metadata object emitted from the
-        service-side of the RPC.
-    """
+        Args:
+          initial_metadata: The initial metadata object emitted from the
+            service-side of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def response(self, response):
         """Receives a response from the service-side of the RPC.
 
-    Args:
-      response: A response object emitted from the service-side of the RPC.
-    """
+        Args:
+          response: A response object emitted from the service-side of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def complete(self, terminal_metadata, code, details):
         """Receives the completion values emitted from the service-side of the RPC.
 
-    Args:
-      terminal_metadata: The terminal metadata object emitted from the
-        service-side of the RPC.
-      code: The code object emitted from the service-side of the RPC.
-      details: The details object emitted from the service-side of the RPC.
-    """
+        Args:
+          terminal_metadata: The terminal metadata object emitted from the
+            service-side of the RPC.
+          code: The code object emitted from the service-side of the RPC.
+          details: The details object emitted from the service-side of the RPC.
+        """
         raise NotImplementedError()
 
 
@@ -353,77 +360,81 @@ class UnaryUnaryMultiCallable(abc.ABC):
     """Affords invoking a unary-unary RPC in any call style."""
 
     @abc.abstractmethod
-    def __call__(self,
-                 request,
-                 timeout,
-                 metadata=None,
-                 with_call=False,
-                 protocol_options=None):
+    def __call__(
+        self,
+        request,
+        timeout,
+        metadata=None,
+        with_call=False,
+        protocol_options=None,
+    ):
         """Synchronously invokes the underlying RPC.
 
-    Args:
-      request: The request value for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      with_call: Whether or not to include return a Call for the RPC in addition
-        to the response.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      The response value for the RPC, and a Call for the RPC if with_call was
-        set to True at invocation.
-
-    Raises:
-      AbortionError: Indicating that the RPC was aborted.
-    """
+        Args:
+          request: The request value for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          with_call: Whether or not to include return a Call for the RPC in addition
+            to the response.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          The response value for the RPC, and a Call for the RPC if with_call was
+            set to True at invocation.
+
+        Raises:
+          AbortionError: Indicating that the RPC was aborted.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def future(self, request, timeout, metadata=None, protocol_options=None):
         """Asynchronously invokes the underlying RPC.
 
-    Args:
-      request: The request value for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and a future.Future. In the
-        event of RPC completion, the return Future's result value will be the
-        response value of the RPC. In the event of RPC abortion, the returned
-        Future's exception value will be an AbortionError.
-    """
+        Args:
+          request: The request value for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and a future.Future. In the
+            event of RPC completion, the return Future's result value will be the
+            response value of the RPC. In the event of RPC abortion, the returned
+            Future's exception value will be an AbortionError.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event(self,
-              request,
-              receiver,
-              abortion_callback,
-              timeout,
-              metadata=None,
-              protocol_options=None):
+    def event(
+        self,
+        request,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Asynchronously invokes the underlying RPC.
 
-    Args:
-      request: The request value for the RPC.
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A Call for the RPC.
-    """
+        Args:
+          request: The request value for the RPC.
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A Call for the RPC.
+        """
         raise NotImplementedError()
 
 
@@ -434,45 +445,47 @@ class UnaryStreamMultiCallable(abc.ABC):
     def __call__(self, request, timeout, metadata=None, protocol_options=None):
         """Invokes the underlying RPC.
 
-    Args:
-      request: The request value for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and an iterator of response
-        values. Drawing response values from the returned iterator may raise
-        AbortionError indicating abortion of the RPC.
-    """
+        Args:
+          request: The request value for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and an iterator of response
+            values. Drawing response values from the returned iterator may raise
+            AbortionError indicating abortion of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event(self,
-              request,
-              receiver,
-              abortion_callback,
-              timeout,
-              metadata=None,
-              protocol_options=None):
+    def event(
+        self,
+        request,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Asynchronously invokes the underlying RPC.
 
-    Args:
-      request: The request value for the RPC.
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A Call object for the RPC.
-    """
+        Args:
+          request: The request value for the RPC.
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A Call object for the RPC.
+        """
         raise NotImplementedError()
 
 
@@ -480,80 +493,82 @@ class StreamUnaryMultiCallable(abc.ABC):
     """Affords invoking a stream-unary RPC in any call style."""
 
     @abc.abstractmethod
-    def __call__(self,
-                 request_iterator,
-                 timeout,
-                 metadata=None,
-                 with_call=False,
-                 protocol_options=None):
+    def __call__(
+        self,
+        request_iterator,
+        timeout,
+        metadata=None,
+        with_call=False,
+        protocol_options=None,
+    ):
         """Synchronously invokes the underlying RPC.
 
-    Args:
-      request_iterator: An iterator that yields request values for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      with_call: Whether or not to include return a Call for the RPC in addition
-        to the response.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      The response value for the RPC, and a Call for the RPC if with_call was
-        set to True at invocation.
-
-    Raises:
-      AbortionError: Indicating that the RPC was aborted.
-    """
+        Args:
+          request_iterator: An iterator that yields request values for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          with_call: Whether or not to include return a Call for the RPC in addition
+            to the response.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          The response value for the RPC, and a Call for the RPC if with_call was
+            set to True at invocation.
+
+        Raises:
+          AbortionError: Indicating that the RPC was aborted.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def future(self,
-               request_iterator,
-               timeout,
-               metadata=None,
-               protocol_options=None):
+    def future(
+        self, request_iterator, timeout, metadata=None, protocol_options=None
+    ):
         """Asynchronously invokes the underlying RPC.
 
-    Args:
-      request_iterator: An iterator that yields request values for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and a future.Future. In the
-        event of RPC completion, the return Future's result value will be the
-        response value of the RPC. In the event of RPC abortion, the returned
-        Future's exception value will be an AbortionError.
-    """
+        Args:
+          request_iterator: An iterator that yields request values for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and a future.Future. In the
+            event of RPC completion, the return Future's result value will be the
+            response value of the RPC. In the event of RPC abortion, the returned
+            Future's exception value will be an AbortionError.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event(self,
-              receiver,
-              abortion_callback,
-              timeout,
-              metadata=None,
-              protocol_options=None):
+    def event(
+        self,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Asynchronously invokes the underlying RPC.
 
-    Args:
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A single object that is both a Call object for the RPC and a
-        stream.Consumer to which the request values of the RPC should be passed.
-    """
+        Args:
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A single object that is both a Call object for the RPC and a
+            stream.Consumer to which the request values of the RPC should be passed.
+        """
         raise NotImplementedError()
 
 
@@ -561,97 +576,97 @@ class StreamStreamMultiCallable(abc.ABC):
     """Affords invoking a stream-stream RPC in any call style."""
 
     @abc.abstractmethod
-    def __call__(self,
-                 request_iterator,
-                 timeout,
-                 metadata=None,
-                 protocol_options=None):
+    def __call__(
+        self, request_iterator, timeout, metadata=None, protocol_options=None
+    ):
         """Invokes the underlying RPC.
 
-    Args:
-      request_iterator: An iterator that yields request values for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and an iterator of response
-        values. Drawing response values from the returned iterator may raise
-        AbortionError indicating abortion of the RPC.
-    """
+        Args:
+          request_iterator: An iterator that yields request values for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and an iterator of response
+            values. Drawing response values from the returned iterator may raise
+            AbortionError indicating abortion of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event(self,
-              receiver,
-              abortion_callback,
-              timeout,
-              metadata=None,
-              protocol_options=None):
+    def event(
+        self,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Asynchronously invokes the underlying RPC.
 
-    Args:
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of
-        the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A single object that is both a Call object for the RPC and a
-        stream.Consumer to which the request values of the RPC should be passed.
-    """
+        Args:
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of
+            the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A single object that is both a Call object for the RPC and a
+            stream.Consumer to which the request values of the RPC should be passed.
+        """
         raise NotImplementedError()
 
 
 class MethodImplementation(abc.ABC):
     """A sum type that describes a method implementation.
 
-  Attributes:
-    cardinality: A cardinality.Cardinality value.
-    style: A style.Service value.
-    unary_unary_inline: The implementation of the method as a callable value
-      that takes a request value and a ServicerContext object and returns a
-      response value. Only non-None if cardinality is
-      cardinality.Cardinality.UNARY_UNARY and style is style.Service.INLINE.
-    unary_stream_inline: The implementation of the method as a callable value
-      that takes a request value and a ServicerContext object and returns an
-      iterator of response values. Only non-None if cardinality is
-      cardinality.Cardinality.UNARY_STREAM and style is style.Service.INLINE.
-    stream_unary_inline: The implementation of the method as a callable value
-      that takes an iterator of request values and a ServicerContext object and
-      returns a response value. Only non-None if cardinality is
-      cardinality.Cardinality.STREAM_UNARY and style is style.Service.INLINE.
-    stream_stream_inline: The implementation of the method as a callable value
-      that takes an iterator of request values and a ServicerContext object and
-      returns an iterator of response values. Only non-None if cardinality is
-      cardinality.Cardinality.STREAM_STREAM and style is style.Service.INLINE.
-    unary_unary_event: The implementation of the method as a callable value that
-      takes a request value, a response callback to which to pass the response
-      value of the RPC, and a ServicerContext. Only non-None if cardinality is
-      cardinality.Cardinality.UNARY_UNARY and style is style.Service.EVENT.
-    unary_stream_event: The implementation of the method as a callable value
-      that takes a request value, a stream.Consumer to which to pass the
-      response values of the RPC, and a ServicerContext. Only non-None if
-      cardinality is cardinality.Cardinality.UNARY_STREAM and style is
-      style.Service.EVENT.
-    stream_unary_event: The implementation of the method as a callable value
-      that takes a response callback to which to pass the response value of the
-      RPC and a ServicerContext and returns a stream.Consumer to which the
-      request values of the RPC should be passed. Only non-None if cardinality
-      is cardinality.Cardinality.STREAM_UNARY and style is style.Service.EVENT.
-    stream_stream_event: The implementation of the method as a callable value
-      that takes a stream.Consumer to which to pass the response values of the
-      RPC and a ServicerContext and returns a stream.Consumer to which the
-      request values of the RPC should be passed. Only non-None if cardinality
-      is cardinality.Cardinality.STREAM_STREAM and style is
-      style.Service.EVENT.
-  """
+    Attributes:
+      cardinality: A cardinality.Cardinality value.
+      style: A style.Service value.
+      unary_unary_inline: The implementation of the method as a callable value
+        that takes a request value and a ServicerContext object and returns a
+        response value. Only non-None if cardinality is
+        cardinality.Cardinality.UNARY_UNARY and style is style.Service.INLINE.
+      unary_stream_inline: The implementation of the method as a callable value
+        that takes a request value and a ServicerContext object and returns an
+        iterator of response values. Only non-None if cardinality is
+        cardinality.Cardinality.UNARY_STREAM and style is style.Service.INLINE.
+      stream_unary_inline: The implementation of the method as a callable value
+        that takes an iterator of request values and a ServicerContext object and
+        returns a response value. Only non-None if cardinality is
+        cardinality.Cardinality.STREAM_UNARY and style is style.Service.INLINE.
+      stream_stream_inline: The implementation of the method as a callable value
+        that takes an iterator of request values and a ServicerContext object and
+        returns an iterator of response values. Only non-None if cardinality is
+        cardinality.Cardinality.STREAM_STREAM and style is style.Service.INLINE.
+      unary_unary_event: The implementation of the method as a callable value that
+        takes a request value, a response callback to which to pass the response
+        value of the RPC, and a ServicerContext. Only non-None if cardinality is
+        cardinality.Cardinality.UNARY_UNARY and style is style.Service.EVENT.
+      unary_stream_event: The implementation of the method as a callable value
+        that takes a request value, a stream.Consumer to which to pass the
+        response values of the RPC, and a ServicerContext. Only non-None if
+        cardinality is cardinality.Cardinality.UNARY_STREAM and style is
+        style.Service.EVENT.
+      stream_unary_event: The implementation of the method as a callable value
+        that takes a response callback to which to pass the response value of the
+        RPC and a ServicerContext and returns a stream.Consumer to which the
+        request values of the RPC should be passed. Only non-None if cardinality
+        is cardinality.Cardinality.STREAM_UNARY and style is style.Service.EVENT.
+      stream_stream_event: The implementation of the method as a callable value
+        that takes a stream.Consumer to which to pass the response values of the
+        RPC and a ServicerContext and returns a stream.Consumer to which the
+        request values of the RPC should be passed. Only non-None if cardinality
+        is cardinality.Cardinality.STREAM_STREAM and style is
+        style.Service.EVENT.
+    """
 
 
 class MultiMethodImplementation(abc.ABC):
@@ -661,27 +676,27 @@ class MultiMethodImplementation(abc.ABC):
     def service(self, group, method, response_consumer, context):
         """Services an RPC.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      response_consumer: A stream.Consumer to be called to accept the response
-        values of the RPC.
-      context: a ServicerContext object.
-
-    Returns:
-      A stream.Consumer with which to accept the request values of the RPC. The
-        consumer returned from this method may or may not be invoked to
-        completion: in the case of RPC abortion, RPC Framework will simply stop
-        passing values to this object. Implementations must not assume that this
-        object will be called to completion of the request stream or even called
-        at all.
-
-    Raises:
-      abandonment.Abandoned: May or may not be raised when the RPC has been
-        aborted.
-      NoSuchMethodError: If this MultiMethod does not recognize the given group
-        and name for the RPC and is not able to service the RPC.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          response_consumer: A stream.Consumer to be called to accept the response
+            values of the RPC.
+          context: a ServicerContext object.
+
+        Returns:
+          A stream.Consumer with which to accept the request values of the RPC. The
+            consumer returned from this method may or may not be invoked to
+            completion: in the case of RPC abortion, RPC Framework will simply stop
+            passing values to this object. Implementations must not assume that this
+            object will be called to completion of the request stream or even called
+            at all.
+
+        Raises:
+          abandonment.Abandoned: May or may not be raised when the RPC has been
+            aborted.
+          NoSuchMethodError: If this MultiMethod does not recognize the given group
+            and name for the RPC and is not able to service the RPC.
+        """
         raise NotImplementedError()
 
 
@@ -689,361 +704,381 @@ class GenericStub(abc.ABC):
     """Affords RPC invocation via generic methods."""
 
     @abc.abstractmethod
-    def blocking_unary_unary(self,
-                             group,
-                             method,
-                             request,
-                             timeout,
-                             metadata=None,
-                             with_call=False,
-                             protocol_options=None):
+    def blocking_unary_unary(
+        self,
+        group,
+        method,
+        request,
+        timeout,
+        metadata=None,
+        with_call=False,
+        protocol_options=None,
+    ):
         """Invokes a unary-request-unary-response method.
 
-    This method blocks until either returning the response value of the RPC
-    (in the event of RPC completion) or raising an exception (in the event of
-    RPC abortion).
-
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request: The request value for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      with_call: Whether or not to include return a Call for the RPC in addition
-        to the response.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      The response value for the RPC, and a Call for the RPC if with_call was
-        set to True at invocation.
-
-    Raises:
-      AbortionError: Indicating that the RPC was aborted.
-    """
+        This method blocks until either returning the response value of the RPC
+        (in the event of RPC completion) or raising an exception (in the event of
+        RPC abortion).
+
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request: The request value for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          with_call: Whether or not to include return a Call for the RPC in addition
+            to the response.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          The response value for the RPC, and a Call for the RPC if with_call was
+            set to True at invocation.
+
+        Raises:
+          AbortionError: Indicating that the RPC was aborted.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def future_unary_unary(self,
-                           group,
-                           method,
-                           request,
-                           timeout,
-                           metadata=None,
-                           protocol_options=None):
+    def future_unary_unary(
+        self,
+        group,
+        method,
+        request,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Invokes a unary-request-unary-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request: The request value for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and a future.Future. In the
-        event of RPC completion, the return Future's result value will be the
-        response value of the RPC. In the event of RPC abortion, the returned
-        Future's exception value will be an AbortionError.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request: The request value for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and a future.Future. In the
+            event of RPC completion, the return Future's result value will be the
+            response value of the RPC. In the event of RPC abortion, the returned
+            Future's exception value will be an AbortionError.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def inline_unary_stream(self,
-                            group,
-                            method,
-                            request,
-                            timeout,
-                            metadata=None,
-                            protocol_options=None):
+    def inline_unary_stream(
+        self,
+        group,
+        method,
+        request,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Invokes a unary-request-stream-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request: The request value for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and an iterator of response
-        values. Drawing response values from the returned iterator may raise
-        AbortionError indicating abortion of the RPC.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request: The request value for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and an iterator of response
+            values. Drawing response values from the returned iterator may raise
+            AbortionError indicating abortion of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def blocking_stream_unary(self,
-                              group,
-                              method,
-                              request_iterator,
-                              timeout,
-                              metadata=None,
-                              with_call=False,
-                              protocol_options=None):
+    def blocking_stream_unary(
+        self,
+        group,
+        method,
+        request_iterator,
+        timeout,
+        metadata=None,
+        with_call=False,
+        protocol_options=None,
+    ):
         """Invokes a stream-request-unary-response method.
 
-    This method blocks until either returning the response value of the RPC
-    (in the event of RPC completion) or raising an exception (in the event of
-    RPC abortion).
-
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request_iterator: An iterator that yields request values for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      with_call: Whether or not to include return a Call for the RPC in addition
-        to the response.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      The response value for the RPC, and a Call for the RPC if with_call was
-        set to True at invocation.
-
-    Raises:
-      AbortionError: Indicating that the RPC was aborted.
-    """
+        This method blocks until either returning the response value of the RPC
+        (in the event of RPC completion) or raising an exception (in the event of
+        RPC abortion).
+
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request_iterator: An iterator that yields request values for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          with_call: Whether or not to include return a Call for the RPC in addition
+            to the response.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          The response value for the RPC, and a Call for the RPC if with_call was
+            set to True at invocation.
+
+        Raises:
+          AbortionError: Indicating that the RPC was aborted.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def future_stream_unary(self,
-                            group,
-                            method,
-                            request_iterator,
-                            timeout,
-                            metadata=None,
-                            protocol_options=None):
+    def future_stream_unary(
+        self,
+        group,
+        method,
+        request_iterator,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Invokes a stream-request-unary-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request_iterator: An iterator that yields request values for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and a future.Future. In the
-        event of RPC completion, the return Future's result value will be the
-        response value of the RPC. In the event of RPC abortion, the returned
-        Future's exception value will be an AbortionError.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request_iterator: An iterator that yields request values for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and a future.Future. In the
+            event of RPC completion, the return Future's result value will be the
+            response value of the RPC. In the event of RPC abortion, the returned
+            Future's exception value will be an AbortionError.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def inline_stream_stream(self,
-                             group,
-                             method,
-                             request_iterator,
-                             timeout,
-                             metadata=None,
-                             protocol_options=None):
+    def inline_stream_stream(
+        self,
+        group,
+        method,
+        request_iterator,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Invokes a stream-request-stream-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request_iterator: An iterator that yields request values for the RPC.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      An object that is both a Call for the RPC and an iterator of response
-        values. Drawing response values from the returned iterator may raise
-        AbortionError indicating abortion of the RPC.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request_iterator: An iterator that yields request values for the RPC.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          An object that is both a Call for the RPC and an iterator of response
+            values. Drawing response values from the returned iterator may raise
+            AbortionError indicating abortion of the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event_unary_unary(self,
-                          group,
-                          method,
-                          request,
-                          receiver,
-                          abortion_callback,
-                          timeout,
-                          metadata=None,
-                          protocol_options=None):
+    def event_unary_unary(
+        self,
+        group,
+        method,
+        request,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Event-driven invocation of a unary-request-unary-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request: The request value for the RPC.
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A Call for the RPC.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request: The request value for the RPC.
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A Call for the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event_unary_stream(self,
-                           group,
-                           method,
-                           request,
-                           receiver,
-                           abortion_callback,
-                           timeout,
-                           metadata=None,
-                           protocol_options=None):
+    def event_unary_stream(
+        self,
+        group,
+        method,
+        request,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Event-driven invocation of a unary-request-stream-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      request: The request value for the RPC.
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A Call for the RPC.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          request: The request value for the RPC.
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A Call for the RPC.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event_stream_unary(self,
-                           group,
-                           method,
-                           receiver,
-                           abortion_callback,
-                           timeout,
-                           metadata=None,
-                           protocol_options=None):
+    def event_stream_unary(
+        self,
+        group,
+        method,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Event-driven invocation of a unary-request-unary-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A pair of a Call object for the RPC and a stream.Consumer to which the
-        request values of the RPC should be passed.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A pair of a Call object for the RPC and a stream.Consumer to which the
+            request values of the RPC should be passed.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def event_stream_stream(self,
-                            group,
-                            method,
-                            receiver,
-                            abortion_callback,
-                            timeout,
-                            metadata=None,
-                            protocol_options=None):
+    def event_stream_stream(
+        self,
+        group,
+        method,
+        receiver,
+        abortion_callback,
+        timeout,
+        metadata=None,
+        protocol_options=None,
+    ):
         """Event-driven invocation of a unary-request-stream-response method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
-      receiver: A ResponseReceiver to be passed the response data of the RPC.
-      abortion_callback: A callback to be called and passed an Abortion value
-        in the event of RPC abortion.
-      timeout: A duration of time in seconds to allow for the RPC.
-      metadata: A metadata value to be passed to the service-side of the RPC.
-      protocol_options: A value specified by the provider of a Face interface
-        implementation affording custom state and behavior.
-
-    Returns:
-      A pair of a Call object for the RPC and a stream.Consumer to which the
-        request values of the RPC should be passed.
-    """
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
+          receiver: A ResponseReceiver to be passed the response data of the RPC.
+          abortion_callback: A callback to be called and passed an Abortion value
+            in the event of RPC abortion.
+          timeout: A duration of time in seconds to allow for the RPC.
+          metadata: A metadata value to be passed to the service-side of the RPC.
+          protocol_options: A value specified by the provider of a Face interface
+            implementation affording custom state and behavior.
+
+        Returns:
+          A pair of a Call object for the RPC and a stream.Consumer to which the
+            request values of the RPC should be passed.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def unary_unary(self, group, method):
         """Creates a UnaryUnaryMultiCallable for a unary-unary method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
 
-    Returns:
-      A UnaryUnaryMultiCallable value for the named unary-unary method.
-    """
+        Returns:
+          A UnaryUnaryMultiCallable value for the named unary-unary method.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def unary_stream(self, group, method):
         """Creates a UnaryStreamMultiCallable for a unary-stream method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
 
-    Returns:
-      A UnaryStreamMultiCallable value for the name unary-stream method.
-    """
+        Returns:
+          A UnaryStreamMultiCallable value for the name unary-stream method.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def stream_unary(self, group, method):
         """Creates a StreamUnaryMultiCallable for a stream-unary method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
 
-    Returns:
-      A StreamUnaryMultiCallable value for the named stream-unary method.
-    """
+        Returns:
+          A StreamUnaryMultiCallable value for the named stream-unary method.
+        """
         raise NotImplementedError()
 
     @abc.abstractmethod
     def stream_stream(self, group, method):
         """Creates a StreamStreamMultiCallable for a stream-stream method.
 
-    Args:
-      group: The group identifier of the RPC.
-      method: The method identifier of the RPC.
+        Args:
+          group: The group identifier of the RPC.
+          method: The method identifier of the RPC.
 
-    Returns:
-      A StreamStreamMultiCallable value for the named stream-stream method.
-    """
+        Returns:
+          A StreamStreamMultiCallable value for the named stream-stream method.
+        """
         raise NotImplementedError()
 
 
 class DynamicStub(abc.ABC):
     """Affords RPC invocation via attributes corresponding to afforded methods.
 
-  Instances of this type may be scoped to a single group so that attribute
-  access is unambiguous.
-
-  Instances of this type respond to attribute access as follows: if the
-  requested attribute is the name of a unary-unary method, the value of the
-  attribute will be a UnaryUnaryMultiCallable with which to invoke an RPC; if
-  the requested attribute is the name of a unary-stream method, the value of the
-  attribute will be a UnaryStreamMultiCallable with which to invoke an RPC; if
-  the requested attribute is the name of a stream-unary method, the value of the
-  attribute will be a StreamUnaryMultiCallable with which to invoke an RPC; and
-  if the requested attribute is the name of a stream-stream method, the value of
-  the attribute will be a StreamStreamMultiCallable with which to invoke an RPC.
-  """
+    Instances of this type may be scoped to a single group so that attribute
+    access is unambiguous.
+
+    Instances of this type respond to attribute access as follows: if the
+    requested attribute is the name of a unary-unary method, the value of the
+    attribute will be a UnaryUnaryMultiCallable with which to invoke an RPC; if
+    the requested attribute is the name of a unary-stream method, the value of the
+    attribute will be a UnaryStreamMultiCallable with which to invoke an RPC; if
+    the requested attribute is the name of a stream-unary method, the value of the
+    attribute will be a StreamUnaryMultiCallable with which to invoke an RPC; and
+    if the requested attribute is the name of a stream-stream method, the value of
+    the attribute will be a StreamStreamMultiCallable with which to invoke an RPC.
+    """
diff --git a/contrib/python/grpcio/py3/grpc/framework/interfaces/face/utilities.py b/contrib/python/grpcio/py3/grpc/framework/interfaces/face/utilities.py
index f27bd676155..01807a16026 100644
--- a/contrib/python/grpcio/py3/grpc/framework/interfaces/face/utilities.py
+++ b/contrib/python/grpcio/py3/grpc/framework/interfaces/face/utilities.py
@@ -22,147 +22,224 @@ from grpc.framework.foundation import stream  # pylint: disable=unused-import
 from grpc.framework.interfaces.face import face
 
 
-class _MethodImplementation(face.MethodImplementation,
-                            collections.namedtuple('_MethodImplementation', [
-                                'cardinality',
-                                'style',
-                                'unary_unary_inline',
-                                'unary_stream_inline',
-                                'stream_unary_inline',
-                                'stream_stream_inline',
-                                'unary_unary_event',
-                                'unary_stream_event',
-                                'stream_unary_event',
-                                'stream_stream_event',
-                            ])):
+class _MethodImplementation(
+    face.MethodImplementation,
+    collections.namedtuple(
+        "_MethodImplementation",
+        [
+            "cardinality",
+            "style",
+            "unary_unary_inline",
+            "unary_stream_inline",
+            "stream_unary_inline",
+            "stream_stream_inline",
+            "unary_unary_event",
+            "unary_stream_event",
+            "stream_unary_event",
+            "stream_stream_event",
+        ],
+    ),
+):
     pass
 
 
 def unary_unary_inline(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a unary-unary RPC method as a callable value
-      that takes a request value and an face.ServicerContext object and
-      returns a response value.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.UNARY_UNARY,
-                                 style.Service.INLINE, behavior, None, None,
-                                 None, None, None, None, None)
+    Args:
+      behavior: The implementation of a unary-unary RPC method as a callable value
+        that takes a request value and an face.ServicerContext object and
+        returns a response value.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.UNARY_UNARY,
+        style.Service.INLINE,
+        behavior,
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+    )
 
 
 def unary_stream_inline(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a unary-stream RPC method as a callable
-      value that takes a request value and an face.ServicerContext object and
-      returns an iterator of response values.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.UNARY_STREAM,
-                                 style.Service.INLINE, None, behavior, None,
-                                 None, None, None, None, None)
+    Args:
+      behavior: The implementation of a unary-stream RPC method as a callable
+        value that takes a request value and an face.ServicerContext object and
+        returns an iterator of response values.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.UNARY_STREAM,
+        style.Service.INLINE,
+        None,
+        behavior,
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+    )
 
 
 def stream_unary_inline(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a stream-unary RPC method as a callable
-      value that takes an iterator of request values and an
-      face.ServicerContext object and returns a response value.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.STREAM_UNARY,
-                                 style.Service.INLINE, None, None, behavior,
-                                 None, None, None, None, None)
+    Args:
+      behavior: The implementation of a stream-unary RPC method as a callable
+        value that takes an iterator of request values and an
+        face.ServicerContext object and returns a response value.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.STREAM_UNARY,
+        style.Service.INLINE,
+        None,
+        None,
+        behavior,
+        None,
+        None,
+        None,
+        None,
+        None,
+    )
 
 
 def stream_stream_inline(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a stream-stream RPC method as a callable
-      value that takes an iterator of request values and an
-      face.ServicerContext object and returns an iterator of response values.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.STREAM_STREAM,
-                                 style.Service.INLINE, None, None, None,
-                                 behavior, None, None, None, None)
+    Args:
+      behavior: The implementation of a stream-stream RPC method as a callable
+        value that takes an iterator of request values and an
+        face.ServicerContext object and returns an iterator of response values.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.STREAM_STREAM,
+        style.Service.INLINE,
+        None,
+        None,
+        None,
+        behavior,
+        None,
+        None,
+        None,
+        None,
+    )
 
 
 def unary_unary_event(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a unary-unary RPC method as a callable
-      value that takes a request value, a response callback to which to pass
-      the response value of the RPC, and an face.ServicerContext.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.UNARY_UNARY,
-                                 style.Service.EVENT, None, None, None, None,
-                                 behavior, None, None, None)
+    Args:
+      behavior: The implementation of a unary-unary RPC method as a callable
+        value that takes a request value, a response callback to which to pass
+        the response value of the RPC, and an face.ServicerContext.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.UNARY_UNARY,
+        style.Service.EVENT,
+        None,
+        None,
+        None,
+        None,
+        behavior,
+        None,
+        None,
+        None,
+    )
 
 
 def unary_stream_event(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a unary-stream RPC method as a callable
-      value that takes a request value, a stream.Consumer to which to pass the
-      the response values of the RPC, and an face.ServicerContext.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.UNARY_STREAM,
-                                 style.Service.EVENT, None, None, None, None,
-                                 None, behavior, None, None)
+    Args:
+      behavior: The implementation of a unary-stream RPC method as a callable
+        value that takes a request value, a stream.Consumer to which to pass the
+        the response values of the RPC, and an face.ServicerContext.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.UNARY_STREAM,
+        style.Service.EVENT,
+        None,
+        None,
+        None,
+        None,
+        None,
+        behavior,
+        None,
+        None,
+    )
 
 
 def stream_unary_event(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a stream-unary RPC method as a callable
-      value that takes a response callback to which to pass the response value
-      of the RPC and an face.ServicerContext and returns a stream.Consumer to
-      which the request values of the RPC should be passed.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.STREAM_UNARY,
-                                 style.Service.EVENT, None, None, None, None,
-                                 None, None, behavior, None)
+    Args:
+      behavior: The implementation of a stream-unary RPC method as a callable
+        value that takes a response callback to which to pass the response value
+        of the RPC and an face.ServicerContext and returns a stream.Consumer to
+        which the request values of the RPC should be passed.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.STREAM_UNARY,
+        style.Service.EVENT,
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+        behavior,
+        None,
+    )
 
 
 def stream_stream_event(behavior):
     """Creates an face.MethodImplementation for the given behavior.
 
-  Args:
-    behavior: The implementation of a stream-stream RPC method as a callable
-      value that takes a stream.Consumer to which to pass the response values
-      of the RPC and an face.ServicerContext and returns a stream.Consumer to
-      which the request values of the RPC should be passed.
-
-  Returns:
-    An face.MethodImplementation derived from the given behavior.
-  """
-    return _MethodImplementation(cardinality.Cardinality.STREAM_STREAM,
-                                 style.Service.EVENT, None, None, None, None,
-                                 None, None, None, behavior)
+    Args:
+      behavior: The implementation of a stream-stream RPC method as a callable
+        value that takes a stream.Consumer to which to pass the response values
+        of the RPC and an face.ServicerContext and returns a stream.Consumer to
+        which the request values of the RPC should be passed.
+
+    Returns:
+      An face.MethodImplementation derived from the given behavior.
+    """
+    return _MethodImplementation(
+        cardinality.Cardinality.STREAM_STREAM,
+        style.Service.EVENT,
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+        behavior,
+    )