Update contrib/python/traitlets/py3 to 5.11.2

36 files changed, 986 insertions, 226 deletions

diff --git a/contrib/python/traitlets/py3/.dist-info/METADATA b/contrib/python/traitlets/py3/.dist-info/METADATA
index 5ef59abe28f..fb63430a4c1 100644
--- a/contrib/python/traitlets/py3/.dist-info/METADATA
+++ b/contrib/python/traitlets/py3/.dist-info/METADATA
@@ -1,6 +1,6 @@
 Metadata-Version: 2.1
 Name: traitlets
-Version: 5.10.1
+Version: 5.11.2
 Summary: Traitlets Python configuration system
 Project-URL: Homepage, https://github.com/ipython/traitlets
 Author-email: IPython Development Team <[email protected]>
diff --git a/contrib/python/traitlets/py3/tests/__init__.py b/contrib/python/traitlets/py3/tests/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/contrib/python/traitlets/py3/tests/__init__.py
diff --git a/contrib/python/traitlets/py3/traitlets/tests/_warnings.py b/contrib/python/traitlets/py3/tests/_warnings.py
index e3c3a0ac6d6..e3c3a0ac6d6 100644
--- a/contrib/python/traitlets/py3/traitlets/tests/_warnings.py
+++ b/contrib/python/traitlets/py3/tests/_warnings.py
diff --git a/contrib/python/traitlets/py3/tests/config/__init__.py b/contrib/python/traitlets/py3/tests/config/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/contrib/python/traitlets/py3/tests/config/__init__.py
diff --git a/contrib/python/traitlets/py3/traitlets/config/tests/test_application.py b/contrib/python/traitlets/py3/tests/config/test_application.py
index 084ff6f0325..610cafc3cd5 100644
--- a/contrib/python/traitlets/py3/traitlets/config/tests/test_application.py
+++ b/contrib/python/traitlets/py3/tests/config/test_application.py
@@ -601,7 +601,7 @@ class TestApplication(TestCase):
             with self.assertRaises(SyntaxError):
                 app.load_config_file(name, path=[td])
 
-    def test_subcommands_instanciation(self):
+    def test_subcommands_instantiation(self):
         """Try all ways to specify how to create sub-apps."""
         app = Root.instance()
         app.parse_command_line(["sub1"])
@@ -695,7 +695,7 @@ def test_cli_multi_scalar(caplog):
 
 class Root(Application):
     subcommands = {
-        "sub1": ("__tests__.config.tests.test_application.Sub1", "import string"),
+        "sub1": ("__tests__.config.test_application.Sub1", "import string"),
     }
 
 
diff --git a/contrib/python/traitlets/py3/tests/config/test_argcomplete.py b/contrib/python/traitlets/py3/tests/config/test_argcomplete.py
new file mode 100644
index 00000000000..52ed6d2bb2c
--- /dev/null
+++ b/contrib/python/traitlets/py3/tests/config/test_argcomplete.py
@@ -0,0 +1,219 @@
+"""
+Tests for argcomplete handling by traitlets.config.application.Application
+"""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+import io
+import os
+import typing as t
+
+import pytest
+
+argcomplete = pytest.importorskip("argcomplete")
+
+from traitlets import Unicode
+from traitlets.config.application import Application
+from traitlets.config.configurable import Configurable
+from traitlets.config.loader import KVArgParseConfigLoader
+
+
+class ArgcompleteApp(Application):
+    """Override loader to pass through kwargs for argcomplete testing"""
+
+    argcomplete_kwargs: t.Dict[str, t.Any]
+
+    def __init__(self, *args, **kwargs):
+        # For subcommands, inherit argcomplete_kwargs from parent app
+        parent = kwargs.get("parent")
+        super().__init__(*args, **kwargs)
+        if parent:
+            argcomplete_kwargs = getattr(parent, "argcomplete_kwargs", None)
+            if argcomplete_kwargs:
+                self.argcomplete_kwargs = argcomplete_kwargs
+
+    def _create_loader(self, argv, aliases, flags, classes):
+        loader = KVArgParseConfigLoader(
+            argv, aliases, flags, classes=classes, log=self.log, subcommands=self.subcommands
+        )
+        loader._argcomplete_kwargs = self.argcomplete_kwargs  # type: ignore[attr-defined]
+        return loader
+
+
+class SubApp1(ArgcompleteApp):
+    pass
+
+
+class SubApp2(ArgcompleteApp):
+    @classmethod
+    def get_subapp_instance(cls, app: Application) -> Application:
+        app.clear_instance()  # since Application is singleton, need to clear main app
+        return cls.instance(parent=app)  # type: ignore[no-any-return]
+
+
+class MainApp(ArgcompleteApp):
+    subcommands = {
+        "subapp1": (SubApp1, "First subapp"),
+        "subapp2": (SubApp2.get_subapp_instance, "Second subapp"),
+    }
+
+
+class CustomError(Exception):
+    """Helper for exit hook for testing argcomplete"""
+
+    @classmethod
+    def exit(cls, code):
+        raise cls(str(code))
+
+
+class TestArgcomplete:
+    IFS = "\013"
+    COMP_WORDBREAKS = " \t\n\"'><=;|&(:"
+
+    @pytest.fixture
+    def argcomplete_on(self, mocker):
+        """Mostly borrowed from argcomplete's unit test fixtures
+
+        Set up environment variables to mimic those passed by argcomplete
+        """
+        _old_environ = os.environ
+        os.environ = os.environ.copy()  # type: ignore[assignment]
+        os.environ["_ARGCOMPLETE"] = "1"
+        os.environ["_ARC_DEBUG"] = "yes"
+        os.environ["IFS"] = self.IFS
+        os.environ["_ARGCOMPLETE_COMP_WORDBREAKS"] = self.COMP_WORDBREAKS
+
+        # argcomplete==2.0.0 always calls fdopen(9, "w") to open a debug stream,
+        # however this could conflict with file descriptors used by pytest
+        # and lead to obscure errors. Since we are not looking at debug stream
+        # in these tests, just mock this fdopen call out.
+        mocker.patch("os.fdopen")
+        try:
+            yield
+        finally:
+            os.environ = _old_environ
+
+    def run_completer(
+        self,
+        app: ArgcompleteApp,
+        command: str,
+        point: t.Union[str, int, None] = None,
+        **kwargs: t.Any,
+    ) -> t.List[str]:
+        """Mostly borrowed from argcomplete's unit tests
+
+        Modified to take an application instead of an ArgumentParser
+
+        Command is the current command being completed and point is the index
+        into the command where the completion is triggered.
+        """
+        if point is None:
+            point = str(len(command))
+        # Flushing tempfile was leading to CI failures with Bad file descriptor, not sure why.
+        # Fortunately we can just write to a StringIO instead.
+        # print("Writing completions to temp file with mode=", write_mode)
+        # from tempfile import TemporaryFile
+        # with TemporaryFile(mode=write_mode) as t:
+        strio = io.StringIO()
+        os.environ["COMP_LINE"] = command
+        os.environ["COMP_POINT"] = str(point)
+
+        with pytest.raises(CustomError) as cm:
+            app.argcomplete_kwargs = dict(
+                output_stream=strio, exit_method=CustomError.exit, **kwargs
+            )
+            app.initialize()
+
+        if str(cm.value) != "0":
+            raise RuntimeError(f"Unexpected exit code {cm.value}")
+        out = strio.getvalue()
+        return out.split(self.IFS)
+
+    def test_complete_simple_app(self, argcomplete_on):
+        app = ArgcompleteApp()
+        expected = [
+            '--help',
+            '--debug',
+            '--show-config',
+            '--show-config-json',
+            '--log-level',
+            '--Application.',
+            '--ArgcompleteApp.',
+        ]
+        assert set(self.run_completer(app, "app --")) == set(expected)
+
+        # completing class traits
+        assert set(self.run_completer(app, "app --App")) > {
+            '--Application.show_config',
+            '--Application.log_level',
+            '--Application.log_format',
+        }
+
+    def test_complete_custom_completers(self, argcomplete_on):
+        app = ArgcompleteApp()
+        # test pre-defined completers for Bool/Enum
+        assert set(self.run_completer(app, "app --Application.log_level=")) > {"DEBUG", "INFO"}
+        assert set(self.run_completer(app, "app --ArgcompleteApp.show_config ")) == {
+            "0",
+            "1",
+            "true",
+            "false",
+        }
+
+        # test custom completer and mid-command completions
+        class CustomCls(Configurable):
+            val = Unicode().tag(
+                config=True, argcompleter=argcomplete.completers.ChoicesCompleter(["foo", "bar"])
+            )
+
+        class CustomApp(ArgcompleteApp):
+            classes = [CustomCls]
+            aliases = {("v", "val"): "CustomCls.val"}
+
+        app = CustomApp()
+        assert self.run_completer(app, "app --val ") == ["foo", "bar"]
+        assert self.run_completer(app, "app --val=") == ["foo", "bar"]
+        assert self.run_completer(app, "app -v ") == ["foo", "bar"]
+        assert self.run_completer(app, "app -v=") == ["foo", "bar"]
+        assert self.run_completer(app, "app --CustomCls.val  ") == ["foo", "bar"]
+        assert self.run_completer(app, "app --CustomCls.val=") == ["foo", "bar"]
+        completions = self.run_completer(app, "app --val= abc xyz", point=10)
+        # fixed in argcomplete >= 2.0 to return latter below
+        assert completions == ["--val=foo", "--val=bar"] or completions == ["foo", "bar"]
+        assert self.run_completer(app, "app --val  --log-level=", point=10) == ["foo", "bar"]
+
+    def test_complete_subcommands(self, argcomplete_on):
+        app = MainApp()
+        assert set(self.run_completer(app, "app ")) >= {"subapp1", "subapp2"}
+        assert set(self.run_completer(app, "app sub")) == {"subapp1", "subapp2"}
+        assert set(self.run_completer(app, "app subapp1")) == {"subapp1"}
+
+    def test_complete_subcommands_subapp1(self, argcomplete_on):
+        # subcommand handling modifies _ARGCOMPLETE env var global state, so
+        # only can test one completion per unit test
+        app = MainApp()
+        try:
+            assert set(self.run_completer(app, "app subapp1 --Sub")) > {
+                '--SubApp1.show_config',
+                '--SubApp1.log_level',
+                '--SubApp1.log_format',
+            }
+        finally:
+            SubApp1.clear_instance()
+
+    def test_complete_subcommands_subapp2(self, argcomplete_on):
+        app = MainApp()
+        try:
+            assert set(self.run_completer(app, "app subapp2 --")) > {
+                '--Application.',
+                '--SubApp2.',
+            }
+        finally:
+            SubApp2.clear_instance()
+
+    def test_complete_subcommands_main(self, argcomplete_on):
+        app = MainApp()
+        completions = set(self.run_completer(app, "app --"))
+        assert completions > {'--Application.', '--MainApp.'}
+        assert "--SubApp1." not in completions and "--SubApp2." not in completions
diff --git a/contrib/python/traitlets/py3/traitlets/config/tests/test_configurable.py b/contrib/python/traitlets/py3/tests/config/test_configurable.py
index 357aede78a9..f6499ea29d1 100644
--- a/contrib/python/traitlets/py3/traitlets/config/tests/test_configurable.py
+++ b/contrib/python/traitlets/py3/tests/config/test_configurable.py
@@ -8,6 +8,7 @@ from unittest import TestCase
 
 from pytest import mark
 
+from .._warnings import expected_warnings
 from traitlets.config.application import Application
 from traitlets.config.configurable import Configurable, LoggingConfigurable, SingletonConfigurable
 from traitlets.config.loader import Config
@@ -26,8 +27,6 @@ from traitlets.traitlets import (
 )
 from traitlets.utils.warnings import _deprecations_shown
 
-from traitlets.tests._warnings import expected_warnings
-
 
 class MyConfigurable(Configurable):
     a = Integer(1, help="The integer a.").tag(config=True)
diff --git a/contrib/python/traitlets/py3/traitlets/config/tests/test_loader.py b/contrib/python/traitlets/py3/tests/config/test_loader.py
index 3a1f96120f7..3a1f96120f7 100644
--- a/contrib/python/traitlets/py3/traitlets/config/tests/test_loader.py
+++ b/contrib/python/traitlets/py3/tests/config/test_loader.py
diff --git a/contrib/python/traitlets/py3/traitlets/tests/test_traitlets.py b/contrib/python/traitlets/py3/tests/test_traitlets.py
index dab1f6ddc79..62fa726f19b 100644
--- a/contrib/python/traitlets/py3/traitlets/tests/test_traitlets.py
+++ b/contrib/python/traitlets/py3/tests/test_traitlets.py
@@ -62,7 +62,7 @@ from traitlets import (
 )
 from traitlets.utils import cast_unicode
 
-from traitlets.tests._warnings import expected_warnings
+from ._warnings import expected_warnings
 
 
 def change_dict(*ordered_values):
diff --git a/contrib/python/traitlets/py3/tests/test_traitlets_docstring.py b/contrib/python/traitlets/py3/tests/test_traitlets_docstring.py
new file mode 100644
index 00000000000..700199108f1
--- /dev/null
+++ b/contrib/python/traitlets/py3/tests/test_traitlets_docstring.py
@@ -0,0 +1,84 @@
+"""Tests for traitlets.traitlets."""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+#
+from traitlets import Dict, Instance, Integer, Unicode, Union
+from traitlets.config import Configurable
+
+
+def test_handle_docstring():
+    class SampleConfigurable(Configurable):
+        pass
+
+    class TraitTypesSampleConfigurable(Configurable):
+        """TraitTypesSampleConfigurable docstring"""
+
+        trait_integer = Integer(
+            help="""trait_integer help text""",
+            config=True,
+        )
+        trait_integer_nohelp = Integer(
+            config=True,
+        )
+        trait_integer_noconfig = Integer(
+            help="""trait_integer_noconfig help text""",
+        )
+
+        trait_unicode = Unicode(
+            help="""trait_unicode help text""",
+            config=True,
+        )
+        trait_unicode_nohelp = Unicode(
+            config=True,
+        )
+        trait_unicode_noconfig = Unicode(
+            help="""trait_unicode_noconfig help text""",
+        )
+
+        trait_dict = Dict(
+            help="""trait_dict help text""",
+            config=True,
+        )
+        trait_dict_nohelp = Dict(
+            config=True,
+        )
+        trait_dict_noconfig = Dict(
+            help="""trait_dict_noconfig help text""",
+        )
+
+        trait_instance = Instance(
+            klass=SampleConfigurable,
+            help="""trait_instance help text""",
+            config=True,
+        )
+        trait_instance_nohelp = Instance(
+            klass=SampleConfigurable,
+            config=True,
+        )
+        trait_instance_noconfig = Instance(
+            klass=SampleConfigurable,
+            help="""trait_instance_noconfig help text""",
+        )
+
+        trait_union = Union(
+            [Integer(), Unicode()],
+            help="""trait_union help text""",
+            config=True,
+        )
+        trait_union_nohelp = Union(
+            [Integer(), Unicode()],
+            config=True,
+        )
+        trait_union_noconfig = Union(
+            [Integer(), Unicode()],
+            help="""trait_union_noconfig help text""",
+        )
+
+    base_names = SampleConfigurable().trait_names()
+    for name in TraitTypesSampleConfigurable().trait_names():
+        if name in base_names:
+            continue
+        doc = getattr(TraitTypesSampleConfigurable, name).__doc__
+        if "nohelp" not in name:
+            assert doc == f"{name} help text"
diff --git a/contrib/python/traitlets/py3/traitlets/tests/test_traitlets_enum.py b/contrib/python/traitlets/py3/tests/test_traitlets_enum.py
index c39007e8a05..c39007e8a05 100644
--- a/contrib/python/traitlets/py3/traitlets/tests/test_traitlets_enum.py
+++ b/contrib/python/traitlets/py3/tests/test_traitlets_enum.py
diff --git a/contrib/python/traitlets/py3/tests/test_typing.py b/contrib/python/traitlets/py3/tests/test_typing.py
new file mode 100644
index 00000000000..2b4073ecf72
--- /dev/null
+++ b/contrib/python/traitlets/py3/tests/test_typing.py
@@ -0,0 +1,395 @@
+from __future__ import annotations
+
+import typing
+
+import pytest
+
+from traitlets import (
+    Any,
+    Bool,
+    CInt,
+    Dict,
+    HasTraits,
+    Instance,
+    Int,
+    List,
+    Set,
+    TCPAddress,
+    Type,
+    Unicode,
+    Union,
+    default,
+    observe,
+    validate,
+)
+from traitlets.config import Config
+
+if not typing.TYPE_CHECKING:
+
+    def reveal_type(*args, **kwargs):
+        pass
+
+
+# mypy: disallow-untyped-calls
+
+
+class Foo:
+    def __init__(self, c):
+        self.c = c
+
+
[email protected]_testing
+def mypy_decorator_typing():
+    class T(HasTraits):
+        foo = Unicode("").tag(config=True)
+
+        @default("foo")
+        def _default_foo(self) -> str:
+            return "hi"
+
+        @observe("foo")
+        def _foo_observer(self, change: typing.Any) -> bool:
+            return True
+
+        @validate("foo")
+        def _foo_validate(self, commit: typing.Any) -> bool:
+            return True
+
+    t = T()
+    reveal_type(t.foo)  # R: builtins.str
+    reveal_type(t._foo_observer)  # R: Any
+    reveal_type(t._foo_validate)  # R: Any
+
+
[email protected]_testing
+def mypy_config_typing():
+    c = Config(
+        {
+            "ExtractOutputPreprocessor": {"enabled": True},
+        }
+    )
+    reveal_type(c)  # R: traitlets.config.loader.Config
+
+
[email protected]_testing
+def mypy_union_typing():
+    class T(HasTraits):
+        style = Union(
+            [Unicode("default"), Type(klass=object)],
+            help="Name of the pygments style to use",
+            default_value="hi",
+        ).tag(config=True)
+
+    t = T()
+    reveal_type(Union("foo"))  # R: traitlets.traitlets.Union
+    reveal_type(Union("").tag(sync=True))  # R: traitlets.traitlets.Union
+    reveal_type(Union(None, allow_none=True))  # R: traitlets.traitlets.Union
+    reveal_type(Union(None, allow_none=True).tag(sync=True))  # R: traitlets.traitlets.Union
+    reveal_type(T.style)  # R: traitlets.traitlets.Union
+    reveal_type(t.style)  # R: Any
+
+
[email protected]_testing
+def mypy_list_typing():
+    class T(HasTraits):
+        latex_command = List(
+            ["xelatex", "{filename}", "-quiet"], help="Shell command used to compile latex."
+        ).tag(config=True)
+
+    t = T()
+    reveal_type(List("foo"))  # R: traitlets.traitlets.List
+    reveal_type(List("").tag(sync=True))  # R: traitlets.traitlets.List
+    reveal_type(List(None, allow_none=True))  # R: traitlets.traitlets.List
+    reveal_type(List(None, allow_none=True).tag(sync=True))  # R: traitlets.traitlets.List
+    reveal_type(T.latex_command)  # R: traitlets.traitlets.List
+    reveal_type(t.latex_command)  # R: builtins.list[Any]
+
+
[email protected]_testing
+def mypy_dict_typing():
+    class T(HasTraits):
+        foo = Dict({}, help="Shell command used to compile latex.").tag(config=True)
+
+    t = T()
+    reveal_type(Dict("foo"))  # R: traitlets.traitlets.Dict
+    reveal_type(Dict("").tag(sync=True))  # R: traitlets.traitlets.Dict
+    reveal_type(Dict(None, allow_none=True))  # R: traitlets.traitlets.Dict
+    reveal_type(Dict(None, allow_none=True).tag(sync=True))  # R: traitlets.traitlets.Dict
+    reveal_type(T.foo)  # R: traitlets.traitlets.Dict
+    reveal_type(t.foo)  # R: builtins.dict[Any, Any]
+
+
[email protected]_testing
+def mypy_type_typing():
+    class KernelSpec:
+        item = Unicode("foo")
+
+    class KernelSpecManager(HasTraits):
+        """A manager for kernel specs."""
+
+        kernel_spec_class = Type(
+            KernelSpec,
+            config=True,
+            help="""The kernel spec class.  This is configurable to allow
+            subclassing of the KernelSpecManager for customized behavior.
+            """,
+        )
+        other_class = Type("foo.bar.baz")
+
+    t = KernelSpecManager()
+    reveal_type(t.kernel_spec_class)  # R: def () -> tests.test_typing.KernelSpec@124
+    reveal_type(t.kernel_spec_class())  # R: tests.test_typing.KernelSpec@124
+    reveal_type(t.kernel_spec_class().item)  # R: builtins.str
+    reveal_type(t.other_class)  # R: builtins.type
+    reveal_type(t.other_class())  # R: Any
+
+
[email protected]_testing
+def mypy_unicode_typing():
+    class T(HasTraits):
+        export_format = Unicode(
+            allow_none=False,
+            help="""The export format to be used, either one of the built-in formats
+            or a dotted object name that represents the import path for an
+            ``Exporter`` class""",
+        ).tag(config=True)
+
+    t = T()
+    reveal_type(
+        Unicode(  # R: traitlets.traitlets.Unicode[builtins.str, Union[builtins.str, builtins.bytes]]
+            "foo"
+        )
+    )
+    reveal_type(
+        Unicode(  # R: traitlets.traitlets.Unicode[builtins.str, Union[builtins.str, builtins.bytes]]
+            ""
+        ).tag(
+            sync=True
+        )
+    )
+    reveal_type(
+        Unicode(  # R: traitlets.traitlets.Unicode[Union[builtins.str, None], Union[builtins.str, builtins.bytes, None]]
+            None, allow_none=True
+        )
+    )
+    reveal_type(
+        Unicode(  # R: traitlets.traitlets.Unicode[Union[builtins.str, None], Union[builtins.str, builtins.bytes, None]]
+            None, allow_none=True
+        ).tag(
+            sync=True
+        )
+    )
+    reveal_type(
+        T.export_format  # R: traitlets.traitlets.Unicode[builtins.str, Union[builtins.str, builtins.bytes]]
+    )
+    reveal_type(t.export_format)  # R: builtins.str
+
+
[email protected]_testing
+def mypy_set_typing():
+    class T(HasTraits):
+        remove_cell_tags = Set(
+            Unicode(),
+            default_value=[],
+            help=(
+                "Tags indicating which cells are to be removed,"
+                "matches tags in ``cell.metadata.tags``."
+            ),
+        ).tag(config=True)
+
+        safe_output_keys = Set(
+            config=True,
+            default_value={
+                "metadata",  # Not a mimetype per-se, but expected and safe.
+                "text/plain",
+                "text/latex",
+                "application/json",
+                "image/png",
+                "image/jpeg",
+            },
+            help="Cell output mimetypes to render without modification",
+        )
+
+    t = T()
+    reveal_type(Set("foo"))  # R: traitlets.traitlets.Set
+    reveal_type(Set("").tag(sync=True))  # R: traitlets.traitlets.Set
+    reveal_type(Set(None, allow_none=True))  # R: traitlets.traitlets.Set
+    reveal_type(Set(None, allow_none=True).tag(sync=True))  # R: traitlets.traitlets.Set
+    reveal_type(T.remove_cell_tags)  # R: traitlets.traitlets.Set
+    reveal_type(t.remove_cell_tags)  # R: builtins.set[Any]
+    reveal_type(T.safe_output_keys)  # R: traitlets.traitlets.Set
+    reveal_type(t.safe_output_keys)  # R: builtins.set[Any]
+
+
[email protected]_testing
+def mypy_any_typing():
+    class T(HasTraits):
+        attributes = Any(
+            config=True,
+            default_value={
+                "a": ["href", "title"],
+                "abbr": ["title"],
+                "acronym": ["title"],
+            },
+            help="Allowed HTML tag attributes",
+        )
+
+    t = T()
+    reveal_type(Any("foo"))  # R: traitlets.traitlets.Any
+    reveal_type(Any("").tag(sync=True))  # R: traitlets.traitlets.Any
+    reveal_type(Any(None, allow_none=True))  # R: traitlets.traitlets.Any
+    reveal_type(Any(None, allow_none=True).tag(sync=True))  # R: traitlets.traitlets.Any
+    reveal_type(T.attributes)  # R: traitlets.traitlets.Any
+    reveal_type(t.attributes)  # R: Any
+
+
[email protected]_testing
+def mypy_bool_typing():
+    class T(HasTraits):
+        b = Bool(True).tag(sync=True)
+        ob = Bool(None, allow_none=True).tag(sync=True)
+
+    t = T()
+    reveal_type(
+        Bool(True)  # R: traitlets.traitlets.Bool[builtins.bool, Union[builtins.bool, builtins.int]]
+    )
+    reveal_type(
+        Bool(  # R: traitlets.traitlets.Bool[builtins.bool, Union[builtins.bool, builtins.int]]
+            True
+        ).tag(sync=True)
+    )
+    reveal_type(
+        Bool(  # R: traitlets.traitlets.Bool[Union[builtins.bool, None], Union[builtins.bool, builtins.int, None]]
+            None, allow_none=True
+        )
+    )
+    reveal_type(
+        Bool(  # R: traitlets.traitlets.Bool[Union[builtins.bool, None], Union[builtins.bool, builtins.int, None]]
+            None, allow_none=True
+        ).tag(
+            sync=True
+        )
+    )
+    reveal_type(
+        T.b  # R: traitlets.traitlets.Bool[builtins.bool, Union[builtins.bool, builtins.int]]
+    )
+    reveal_type(t.b)  # R: builtins.bool
+    reveal_type(t.ob)  # R: Union[builtins.bool, None]
+    reveal_type(
+        T.b  # R: traitlets.traitlets.Bool[builtins.bool, Union[builtins.bool, builtins.int]]
+    )
+    reveal_type(
+        T.ob  # R: traitlets.traitlets.Bool[Union[builtins.bool, None], Union[builtins.bool, builtins.int, None]]
+    )
+    # we would expect this to be Optional[Union[bool, int]], but...
+    t.b = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Union[bool, int]")  [assignment]
+    t.b = None  # E: Incompatible types in assignment (expression has type "None", variable has type "Union[bool, int]")  [assignment]
+
+
[email protected]_testing
+def mypy_int_typing():
+    class T(HasTraits):
+        i: Int[int, int] = Int(42).tag(sync=True)
+        oi: Int[int | None, int | None] = Int(42, allow_none=True).tag(sync=True)
+
+    t = T()
+    reveal_type(Int(True))  # R: traitlets.traitlets.Int[builtins.int, builtins.int]
+    reveal_type(Int(True).tag(sync=True))  # R: traitlets.traitlets.Int[builtins.int, builtins.int]
+    reveal_type(
+        Int(  # R: traitlets.traitlets.Int[Union[builtins.int, None], Union[builtins.int, None]]
+            None, allow_none=True
+        )
+    )
+    reveal_type(
+        Int(  # R: traitlets.traitlets.Int[Union[builtins.int, None], Union[builtins.int, None]]
+            None, allow_none=True
+        ).tag(sync=True)
+    )
+    reveal_type(T.i)  # R: traitlets.traitlets.Int[builtins.int, builtins.int]
+    reveal_type(t.i)  # R: builtins.int
+    reveal_type(t.oi)  # R: Union[builtins.int, None]
+    reveal_type(T.i)  # R: traitlets.traitlets.Int[builtins.int, builtins.int]
+    reveal_type(
+        T.oi  # R: traitlets.traitlets.Int[Union[builtins.int, None], Union[builtins.int, None]]
+    )
+    t.i = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]
+    t.i = None  # E: Incompatible types in assignment (expression has type "None", variable has type "int")  [assignment]
+    t.i = 1.2  # E: Incompatible types in assignment (expression has type "float", variable has type "int")  [assignment]
+
+
[email protected]_testing
+def mypy_cint_typing():
+    class T(HasTraits):
+        i = CInt(42).tag(sync=True)
+        oi = CInt(42, allow_none=True).tag(sync=True)
+
+    t = T()
+    reveal_type(CInt(42))  # R: traitlets.traitlets.CInt[builtins.int, Any]
+    reveal_type(CInt(42).tag(sync=True))  # R: traitlets.traitlets.CInt[builtins.int, Any]
+    reveal_type(
+        CInt(None, allow_none=True)  # R: traitlets.traitlets.CInt[Union[builtins.int, None], Any]
+    )
+    reveal_type(
+        CInt(  # R: traitlets.traitlets.CInt[Union[builtins.int, None], Any]
+            None, allow_none=True
+        ).tag(sync=True)
+    )
+    reveal_type(T.i)  # R: traitlets.traitlets.CInt[builtins.int, Any]
+    reveal_type(t.i)  # R: builtins.int
+    reveal_type(t.oi)  # R: Union[builtins.int, None]
+    reveal_type(T.i)  # R: traitlets.traitlets.CInt[builtins.int, Any]
+    reveal_type(T.oi)  # R: traitlets.traitlets.CInt[Union[builtins.int, None], Any]
+
+
[email protected]_testing
+def mypy_tcp_typing():
+    class T(HasTraits):
+        tcp = TCPAddress()
+        otcp = TCPAddress(None, allow_none=True)
+
+    t = T()
+    reveal_type(t.tcp)  # R: Tuple[builtins.str, builtins.int]
+    reveal_type(
+        T.tcp  # R: traitlets.traitlets.TCPAddress[Tuple[builtins.str, builtins.int], Tuple[builtins.str, builtins.int]]
+    )
+    reveal_type(
+        T.tcp.tag(  # R:traitlets.traitlets.TCPAddress[Tuple[builtins.str, builtins.int], Tuple[builtins.str, builtins.int]]
+            sync=True
+        )
+    )
+    reveal_type(t.otcp)  # R: Union[Tuple[builtins.str, builtins.int], None]
+    reveal_type(
+        T.otcp  # R: traitlets.traitlets.TCPAddress[Union[Tuple[builtins.str, builtins.int], None], Union[Tuple[builtins.str, builtins.int], None]]
+    )
+    reveal_type(
+        T.otcp.tag(  # R: traitlets.traitlets.TCPAddress[Union[Tuple[builtins.str, builtins.int], None], Union[Tuple[builtins.str, builtins.int], None]]
+            sync=True
+        )
+    )
+    t.tcp = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Tuple[str, int]")  [assignment]
+    t.otcp = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Optional[Tuple[str, int]]")  [assignment]
+    t.tcp = None  # E: Incompatible types in assignment (expression has type "None", variable has type "Tuple[str, int]")  [assignment]
+
+
[email protected]_testing
+def mypy_instance_typing():
+    class T(HasTraits):
+        inst = Instance(Foo)
+        oinst = Instance(Foo, allow_none=True)
+        oinst_string = Instance("Foo", allow_none=True)
+
+    t = T()
+    reveal_type(t.inst)  # R: tests.test_typing.Foo
+    reveal_type(T.inst)  # R: traitlets.traitlets.Instance[tests.test_typing.Foo]
+    reveal_type(T.inst.tag(sync=True))  # R: traitlets.traitlets.Instance[tests.test_typing.Foo]
+    reveal_type(t.oinst)  # R: Union[tests.test_typing.Foo, None]
+    reveal_type(t.oinst_string)  # R: Union[Any, None]
+    reveal_type(T.oinst)  # R: traitlets.traitlets.Instance[Union[tests.test_typing.Foo, None]]
+    reveal_type(
+        T.oinst.tag(  # R: traitlets.traitlets.Instance[Union[tests.test_typing.Foo, None]]
+            sync=True
+        )
+    )
+    t.inst = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Foo")  [assignment]
+    t.oinst = "foo"  # E: Incompatible types in assignment (expression has type "str", variable has type "Optional[Foo]")  [assignment]
+    t.inst = None  # E: Incompatible types in assignment (expression has type "None", variable has type "Foo")  [assignment]
diff --git a/contrib/python/traitlets/py3/tests/utils/__init__.py b/contrib/python/traitlets/py3/tests/utils/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/contrib/python/traitlets/py3/tests/utils/__init__.py
diff --git a/contrib/python/traitlets/py3/traitlets/utils/tests/test_bunch.py b/contrib/python/traitlets/py3/tests/utils/test_bunch.py
index 223124d7d5e..223124d7d5e 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/tests/test_bunch.py
+++ b/contrib/python/traitlets/py3/tests/utils/test_bunch.py
diff --git a/contrib/python/traitlets/py3/traitlets/utils/tests/test_decorators.py b/contrib/python/traitlets/py3/tests/utils/test_decorators.py
index 5410c201371..d6bf8414e5a 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/tests/test_decorators.py
+++ b/contrib/python/traitlets/py3/tests/utils/test_decorators.py
@@ -1,7 +1,7 @@
 from inspect import Parameter, signature
 from unittest import TestCase
 
-from traitlets.traitlets import HasTraits, Int, Unicode
+from traitlets import HasTraits, Int, Unicode
 from traitlets.utils.decorators import signature_has_traits
 
 
diff --git a/contrib/python/traitlets/py3/traitlets/utils/tests/test_importstring.py b/contrib/python/traitlets/py3/tests/utils/test_importstring.py
index 8ce28add41e..8ce28add41e 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/tests/test_importstring.py
+++ b/contrib/python/traitlets/py3/tests/utils/test_importstring.py
diff --git a/contrib/python/traitlets/py3/tests/ya.make b/contrib/python/traitlets/py3/tests/ya.make
index 6a5cd7cf463..6ffd29993d5 100644
--- a/contrib/python/traitlets/py3/tests/ya.make
+++ b/contrib/python/traitlets/py3/tests/ya.make
@@ -1,20 +1,27 @@
 PY3TEST()
 
 PEERDIR(
+    contrib/python/argcomplete
     contrib/python/traitlets
+    contrib/python/pytest-mock
 )
 
-SRCDIR(contrib/python/traitlets/py3/traitlets)
-
 TEST_SRCS(
-    config/tests/test_application.py
-    config/tests/test_configurable.py
-    config/tests/test_loader.py
-    tests/test_traitlets.py
-    tests/test_traitlets_enum.py
-    utils/tests/test_bunch.py
-    utils/tests/test_decorators.py
-    utils/tests/test_importstring.py
+    __init__.py
+    _warnings.py
+    config/__init__.py
+    config/test_application.py
+    config/test_argcomplete.py
+    config/test_configurable.py
+    config/test_loader.py
+    test_traitlets.py
+    test_traitlets_docstring.py
+    test_traitlets_enum.py
+    test_typing.py
+    utils/__init__.py
+    utils/test_bunch.py
+    utils/test_decorators.py
+    utils/test_importstring.py
 )
 
 NO_LINT()
diff --git a/contrib/python/traitlets/py3/traitlets/__init__.py b/contrib/python/traitlets/py3/traitlets/__init__.py
index 96ebe57f1be..2641c443e9d 100644
--- a/contrib/python/traitlets/py3/traitlets/__init__.py
+++ b/contrib/python/traitlets/py3/traitlets/__init__.py
@@ -1,4 +1,6 @@
 """Traitlets Python configuration system"""
+import typing as _t
+
 from . import traitlets
 from ._version import __version__, version_info
 from .traitlets import *
@@ -19,7 +21,7 @@ __all__ = [
 
 
 class Sentinel(traitlets.Sentinel):  # type:ignore[name-defined]
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args: _t.Any, **kwargs: _t.Any) -> None:
         super().__init__(*args, **kwargs)
         warn(
             """
diff --git a/contrib/python/traitlets/py3/traitlets/_version.py b/contrib/python/traitlets/py3/traitlets/_version.py
index d477cb8ce1b..5fbb9a25992 100644
--- a/contrib/python/traitlets/py3/traitlets/_version.py
+++ b/contrib/python/traitlets/py3/traitlets/_version.py
@@ -5,7 +5,7 @@ import re
 from typing import List
 
 # Version string must appear intact for hatch versioning
-__version__ = "5.10.1"
+__version__ = "5.11.2"
 
 # Build up version_info tuple for backwards compatibility
 pattern = r"(?P<major>\d+).(?P<minor>\d+).(?P<patch>\d+)(?P<rest>.*)"
diff --git a/contrib/python/traitlets/py3/traitlets/config/application.py b/contrib/python/traitlets/py3/traitlets/config/application.py
index fb185f0ae57..5993b4c7f24 100644
--- a/contrib/python/traitlets/py3/traitlets/config/application.py
+++ b/contrib/python/traitlets/py3/traitlets/config/application.py
@@ -2,7 +2,7 @@
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
-
+from __future__ import annotations
 
 import functools
 import json
@@ -17,7 +17,6 @@ from contextlib import suppress
 from copy import deepcopy
 from logging.config import dictConfig
 from textwrap import dedent
-from typing import Any, Callable, TypeVar, cast
 
 from traitlets.config.configurable import Configurable, SingletonConfigurable
 from traitlets.config.loader import (
@@ -40,6 +39,7 @@ from traitlets.traitlets import (
     observe,
     observe_compat,
 )
+from traitlets.utils.bunch import Bunch
 from traitlets.utils.nested_update import nested_update
 from traitlets.utils.text import indent, wrap_paragraphs
 
@@ -95,7 +95,11 @@ else:
 
 IS_PYTHONW = sys.executable and sys.executable.endswith("pythonw.exe")
 
-T = TypeVar("T", bound=Callable[..., Any])
+T = t.TypeVar("T", bound=t.Callable[..., t.Any])
+AnyLogger = t.Union[logging.Logger, logging.LoggerAdapter]
+StrDict = t.Dict[str, t.Any]
+ArgvType = t.Optional[t.List[str]]
+ClassesType = t.List[t.Type[Configurable]]
 
 
 def catch_config_error(method: T) -> T:
@@ -108,7 +112,7 @@ def catch_config_error(method: T) -> T:
     """
 
     @functools.wraps(method)
-    def inner(app, *args, **kwargs):
+    def inner(app: Application, *args: t.Any, **kwargs: t.Any) -> t.Any:
         try:
             return method(app, *args, **kwargs)
         except (TraitError, ArgumentError) as e:
@@ -116,7 +120,7 @@ def catch_config_error(method: T) -> T:
             app.log.debug("Config at the time: %s", app.config)
             app.exit(1)
 
-    return cast(T, inner)
+    return t.cast(T, inner)
 
 
 class ApplicationError(Exception):
@@ -136,7 +140,7 @@ class LevelFormatter(logging.Formatter):
     highlevel_limit = logging.WARN
     highlevel_format = " %(levelname)s |"
 
-    def format(self, record):
+    def format(self, record: logging.LogRecord) -> str:
         if record.levelno >= self.highlevel_limit:
             record.highlevel = self.highlevel_format % record.__dict__
         else:
@@ -149,35 +153,29 @@ class Application(SingletonConfigurable):
 
     # The name of the application, will usually match the name of the command
     # line application
-    name: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode("application")
+    name: str | Unicode[str, str | bytes] = Unicode("application")
 
     # The description of the application that is printed at the beginning
     # of the help.
-    description: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode(
-        "This is an application."
-    )
+    description: str | Unicode[str, str | bytes] = Unicode("This is an application.")
     # default section descriptions
-    option_description: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode(
-        option_description
-    )
-    keyvalue_description: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode(
-        keyvalue_description
-    )
-    subcommand_description: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode(
-        subcommand_description
-    )
+    option_description: str | Unicode[str, str | bytes] = Unicode(option_description)
+    keyvalue_description: str | Unicode[str, str | bytes] = Unicode(keyvalue_description)
+    subcommand_description: str | Unicode[str, str | bytes] = Unicode(subcommand_description)
 
     python_config_loader_class = PyFileConfigLoader
     json_config_loader_class = JSONFileConfigLoader
 
     # The usage and example string that goes at the end of the help string.
-    examples: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode()
+    examples: str | Unicode[str, str | bytes] = Unicode()
 
     # A sequence of Configurable subclasses whose config=True attributes will
     # be exposed at the command line.
-    classes: t.List[t.Type[t.Any]] = []
+    classes: ClassesType = []
 
-    def _classes_inc_parents(self, classes=None):
+    def _classes_inc_parents(
+        self, classes: ClassesType | None = None
+    ) -> t.Generator[type[Configurable], None, None]:
         """Iterate through configurable classes, including configurable parents
 
         :param classes:
@@ -198,18 +196,16 @@ class Application(SingletonConfigurable):
                     yield parent
 
     # The version string of this application.
-    version: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode("0.0")
+    version: str | Unicode[str, str | bytes] = Unicode("0.0")
 
     # the argv used to initialize the application
-    argv: t.Union[t.List[str], List] = List()
+    argv = List()
 
     # Whether failing to load config files should prevent startup
-    raise_config_file_errors: t.Union[bool, Bool[bool, t.Union[bool, int]]] = Bool(
-        TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR
-    )
+    raise_config_file_errors = Bool(TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR)
 
     # The log level for the application
-    log_level: t.Union[str, int, Enum[t.Any, t.Any]] = Enum(
+    log_level = Enum(
         (0, 10, 20, 30, 40, 50, "DEBUG", "INFO", "WARN", "ERROR", "CRITICAL"),
         default_value=logging.WARN,
         help="Set the log level by value or name.",
@@ -217,16 +213,16 @@ class Application(SingletonConfigurable):
 
     _log_formatter_cls = LevelFormatter
 
-    log_datefmt: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode(
+    log_datefmt = Unicode(
         "%Y-%m-%d %H:%M:%S", help="The date format used by logging formatters for %(asctime)s"
     ).tag(config=True)
 
-    log_format: t.Union[str, Unicode[str, t.Union[str, bytes]]] = Unicode(
+    log_format = Unicode(
         "[%(name)s]%(highlevel)s %(message)s",
         help="The Logging format template",
     ).tag(config=True)
 
-    def get_default_logging_config(self):
+    def get_default_logging_config(self) -> StrDict:
         """Return the base logging configuration.
 
         The default is to log to stderr using a StreamHandler, if no default
@@ -239,7 +235,7 @@ class Application(SingletonConfigurable):
         control of logging.
 
         """
-        config: t.Dict[str, t.Any] = {
+        config: StrDict = {
             "version": 1,
             "handlers": {
                 "console": {
@@ -278,7 +274,7 @@ class Application(SingletonConfigurable):
         return config
 
     @observe("log_datefmt", "log_format", "log_level", "logging_config")
-    def _observe_logging_change(self, change):
+    def _observe_logging_change(self, change: Bunch) -> None:
         # convert log level strings to ints
         log_level = self.log_level
         if isinstance(log_level, str):
@@ -286,10 +282,10 @@ class Application(SingletonConfigurable):
         self._configure_logging()
 
     @observe("log", type="default")
-    def _observe_logging_default(self, change):
+    def _observe_logging_default(self, change: Bunch) -> None:
         self._configure_logging()
 
-    def _configure_logging(self):
+    def _configure_logging(self) -> None:
         config = self.get_default_logging_config()
         nested_update(config, self.logging_config or {})
         dictConfig(config)
@@ -297,7 +293,7 @@ class Application(SingletonConfigurable):
         self._logging_configured = True
 
     @default("log")
-    def _log_default(self):
+    def _log_default(self) -> AnyLogger:
         """Start logging for this application."""
         log = logging.getLogger(self.__class__.__name__)
         log.propagate = False
@@ -366,17 +362,13 @@ class Application(SingletonConfigurable):
     #: Values might be like "Class.trait" strings of two-tuples: (Class.trait, help-text),
     #  or just the "Class.trait" string, in which case the help text is inferred from the
     #  corresponding trait
-    aliases: t.Dict[t.Union[str, t.Tuple[str, ...]], t.Union[str, t.Tuple[str, str]]] = {
-        "log-level": "Application.log_level"
-    }
+    aliases: StrDict = {"log-level": "Application.log_level"}
 
     # flags for loading Configurables or store_const style flags
     # flags are loaded from this dict by '--key' flags
     # this must be a dict of two-tuples, the first element being the Config/dict
     # and the second being the help string for the flag
-    flags: t.Dict[
-        t.Union[str, t.Tuple[str, ...]], t.Tuple[t.Union[t.Dict[str, t.Any], Config], str]
-    ] = {
+    flags: StrDict = {
         "debug": (
             {
                 "Application": {
@@ -408,12 +400,12 @@ class Application(SingletonConfigurable):
     # this must be a dict of two-tuples,
     # the first element being the application class/import string
     # and the second being the help string for the subcommand
-    subcommands: t.Union[t.Dict[str, t.Tuple[t.Any, str]], Dict] = Dict()
+    subcommands: dict[str, t.Any] | Dict = Dict()
     # parse_command_line will initialize a subapp, if requested
     subapp = Instance("traitlets.config.application.Application", allow_none=True)
 
     # extra command-line arguments that don't set config values
-    extra_args: t.Union[t.List[str], List] = List(Unicode())
+    extra_args = List(Unicode())
 
     cli_config = Instance(
         Config,
@@ -428,20 +420,20 @@ class Application(SingletonConfigurable):
 
     _loaded_config_files = List()
 
-    show_config: t.Union[bool, Bool[bool, t.Union[bool, int]]] = Bool(
+    show_config = Bool(
         help="Instead of starting the Application, dump configuration to stdout"
     ).tag(config=True)
 
-    show_config_json: t.Union[bool, Bool[bool, t.Union[bool, int]]] = Bool(
+    show_config_json = Bool(
         help="Instead of starting the Application, dump configuration to stdout (as JSON)"
     ).tag(config=True)
 
     @observe("show_config_json")
-    def _show_config_json_changed(self, change):
+    def _show_config_json_changed(self, change: Bunch) -> None:
         self.show_config = change.new
 
     @observe("show_config")
-    def _show_config_changed(self, change):
+    def _show_config_changed(self, change: Bunch) -> None:
         if change.new:
             self._save_start = self.start
             self.start = self.start_show_config  # type:ignore[method-assign]
@@ -460,27 +452,28 @@ class Application(SingletonConfigurable):
 
     @observe("config")
     @observe_compat
-    def _config_changed(self, change):
+    def _config_changed(self, change: Bunch) -> None:
         super()._config_changed(change)
         self.log.debug("Config changed: %r", change.new)
 
     @catch_config_error
-    def initialize(self, argv=None):
+    def initialize(self, argv: ArgvType = None) -> None:
         """Do the basic steps to configure me.
 
         Override in subclasses.
         """
         self.parse_command_line(argv)
 
-    def start(self):
+    def start(self) -> None:
         """Start the app mainloop.
 
         Override in subclasses.
         """
         if self.subapp is not None:
+            assert isinstance(self.subapp, Application)
             return self.subapp.start()
 
-    def start_show_config(self):
+    def start_show_config(self) -> None:
         """start function used when show_config is True"""
         config = self.config.copy()
         # exclude show_config flags from displayed config
@@ -507,28 +500,28 @@ class Application(SingletonConfigurable):
             if not class_config:
                 continue
             print(classname)
-            pformat_kwargs: t.Dict[str, t.Any] = dict(indent=4, compact=True)
+            pformat_kwargs: StrDict = dict(indent=4, compact=True)
 
             for traitname in sorted(class_config):
                 value = class_config[traitname]
                 print(f"  .{traitname} = {pprint.pformat(value, **pformat_kwargs)}")
 
-    def print_alias_help(self):
+    def print_alias_help(self) -> None:
         """Print the alias parts of the help."""
         print("\n".join(self.emit_alias_help()))
 
-    def emit_alias_help(self):
+    def emit_alias_help(self) -> t.Generator[str, None, None]:
         """Yield the lines for alias part of the help."""
         if not self.aliases:
             return
 
-        classdict = {}
+        classdict: dict[str, type[Configurable]] = {}
         for cls in self.classes:
             # include all parents (up to, but excluding Configurable) in available names
             for c in cls.mro()[:-3]:
-                classdict[c.__name__] = c
+                classdict[c.__name__] = t.cast(t.Type[Configurable], c)
 
-        fhelp: t.Optional[str]
+        fhelp: str | None
         for alias, longname in self.aliases.items():
             try:
                 if isinstance(longname, tuple):
@@ -540,27 +533,26 @@ class Application(SingletonConfigurable):
                 cls = classdict[classname]
 
                 trait = cls.class_traits(config=True)[traitname]
-                fhelp = cls.class_get_trait_help(trait, helptext=fhelp).splitlines()
+                fhelp_lines = cls.class_get_trait_help(trait, helptext=fhelp).splitlines()
 
                 if not isinstance(alias, tuple):
-                    alias = (alias,)
+                    alias = (alias,)  # type:ignore[assignment]
                 alias = sorted(alias, key=len)  # type:ignore[assignment]
                 alias = ", ".join(("--%s" if len(m) > 1 else "-%s") % m for m in alias)
 
                 # reformat first line
-                assert fhelp is not None
-                fhelp[0] = fhelp[0].replace("--" + longname, alias)  # type:ignore
-                yield from fhelp
+                fhelp_lines[0] = fhelp_lines[0].replace("--" + longname, alias)
+                yield from fhelp_lines
                 yield indent("Equivalent to: [--%s]" % longname)
             except Exception as ex:
                 self.log.error("Failed collecting help-message for alias %r, due to: %s", alias, ex)
                 raise
 
-    def print_flag_help(self):
+    def print_flag_help(self) -> None:
         """Print the flag part of the help."""
         print("\n".join(self.emit_flag_help()))
 
-    def emit_flag_help(self):
+    def emit_flag_help(self) -> t.Generator[str, None, None]:
         """Yield the lines for the flag part of the help."""
         if not self.flags:
             return
@@ -568,7 +560,7 @@ class Application(SingletonConfigurable):
         for flags, (cfg, fhelp) in self.flags.items():
             try:
                 if not isinstance(flags, tuple):
-                    flags = (flags,)
+                    flags = (flags,)  # type:ignore[assignment]
                 flags = sorted(flags, key=len)  # type:ignore[assignment]
                 flags = ", ".join(("--%s" if len(m) > 1 else "-%s") % m for m in flags)
                 yield flags
@@ -584,11 +576,11 @@ class Application(SingletonConfigurable):
                 self.log.error("Failed collecting help-message for flag %r, due to: %s", flags, ex)
                 raise
 
-    def print_options(self):
+    def print_options(self) -> None:
         """Print the options part of the help."""
         print("\n".join(self.emit_options_help()))
 
-    def emit_options_help(self):
+    def emit_options_help(self) -> t.Generator[str, None, None]:
         """Yield the lines for the options part of the help."""
         if not self.flags and not self.aliases:
             return
@@ -603,11 +595,11 @@ class Application(SingletonConfigurable):
         yield from self.emit_alias_help()
         yield ""
 
-    def print_subcommands(self):
+    def print_subcommands(self) -> None:
         """Print the subcommand part of the help."""
         print("\n".join(self.emit_subcommands_help()))
 
-    def emit_subcommands_help(self):
+    def emit_subcommands_help(self) -> t.Generator[str, None, None]:
         """Yield the lines for the subcommand part of the help."""
         if not self.subcommands:
             return
@@ -624,7 +616,7 @@ class Application(SingletonConfigurable):
                 yield indent(dedent(help.strip()))
         yield ""
 
-    def emit_help_epilogue(self, classes):
+    def emit_help_epilogue(self, classes: bool) -> t.Generator[str, None, None]:
         """Yield the very bottom lines of the help message.
 
         If classes=False (the default), print `--help-all` msg.
@@ -633,14 +625,14 @@ class Application(SingletonConfigurable):
             yield "To see all available configurables, use `--help-all`."
             yield ""
 
-    def print_help(self, classes=False):
+    def print_help(self, classes: bool = False) -> None:
         """Print the help for each Configurable class in self.classes.
 
         If classes=False (the default), only flags and aliases are printed.
         """
         print("\n".join(self.emit_help(classes=classes)))
 
-    def emit_help(self, classes=False):
+    def emit_help(self, classes: bool = False) -> t.Generator[str, None, None]:
         """Yield the help-lines for each Configurable class in self.classes.
 
         If classes=False (the default), only flags and aliases are printed.
@@ -665,28 +657,28 @@ class Application(SingletonConfigurable):
 
         yield from self.emit_help_epilogue(classes)
 
-    def document_config_options(self):
+    def document_config_options(self) -> str:
         """Generate rST format documentation for the config options this application
 
         Returns a multiline string.
         """
         return "\n".join(c.class_config_rst_doc() for c in self._classes_inc_parents())
 
-    def print_description(self):
+    def print_description(self) -> None:
         """Print the application description."""
         print("\n".join(self.emit_description()))
 
-    def emit_description(self):
+    def emit_description(self) -> t.Generator[str, None, None]:
         """Yield lines with the application description."""
         for p in wrap_paragraphs(self.description or self.__doc__ or ""):
             yield p
             yield ""
 
-    def print_examples(self):
+    def print_examples(self) -> None:
         """Print usage and examples (see `emit_examples()`)."""
         print("\n".join(self.emit_examples()))
 
-    def emit_examples(self):
+    def emit_examples(self) -> t.Generator[str, None, None]:
         """Yield lines with the usage and examples.
 
         This usage string goes at the end of the command line help string
@@ -699,12 +691,12 @@ class Application(SingletonConfigurable):
             yield indent(dedent(self.examples.strip()))
             yield ""
 
-    def print_version(self):
+    def print_version(self) -> None:
         """Print the version string."""
         print(self.version)
 
     @catch_config_error
-    def initialize_subcommand(self, subc, argv=None):
+    def initialize_subcommand(self, subc: str, argv: ArgvType = None) -> None:
         """Initialize a subcommand with argv."""
         val = self.subcommands.get(subc)
         assert val is not None
@@ -726,9 +718,9 @@ class Application(SingletonConfigurable):
             raise AssertionError("Invalid mappings for subcommand '%s'!" % subc)
 
         # ... and finally initialize subapp.
-        self.subapp.initialize(argv)
+        self.subapp.initialize(argv)  # type:ignore[union-attr]
 
-    def flatten_flags(self):
+    def flatten_flags(self) -> tuple[dict[str, t.Any], dict[str, t.Any]]:
         """Flatten flags and aliases for loaders, so cl-args override as expected.
 
         This prevents issues such as an alias pointing to InteractiveShell,
@@ -751,11 +743,11 @@ class Application(SingletonConfigurable):
                 mro_tree[parent.__name__].append(clsname)
         # flatten aliases, which have the form:
         # { 'alias' : 'Class.trait' }
-        aliases: t.Dict[str, str] = {}
+        aliases: dict[str, str] = {}
         for alias, longname in self.aliases.items():
             if isinstance(longname, tuple):
                 longname, _ = longname
-            cls, trait = longname.split(".", 1)  # type:ignore
+            cls, trait = longname.split(".", 1)
             children = mro_tree[cls]  # type:ignore[index]
             if len(children) == 1:
                 # exactly one descendent, promote alias
@@ -769,8 +761,8 @@ class Application(SingletonConfigurable):
         # { 'key' : ({'Cls' : {'trait' : value}}, 'help')}
         flags = {}
         for key, (flagdict, help) in self.flags.items():
-            newflag: t.Dict[t.Any, t.Any] = {}
-            for cls, subdict in flagdict.items():  # type:ignore
+            newflag: dict[t.Any, t.Any] = {}
+            for cls, subdict in flagdict.items():
                 children = mro_tree[cls]  # type:ignore[index]
                 # exactly one descendent, promote flag section
                 if len(children) == 1:
@@ -782,18 +774,24 @@ class Application(SingletonConfigurable):
                     newflag[cls] = subdict
 
             if not isinstance(key, tuple):
-                key = (key,)
+                key = (key,)  # type:ignore[assignment]
             for k in key:
                 flags[k] = (newflag, help)
         return flags, aliases
 
-    def _create_loader(self, argv, aliases, flags, classes):
+    def _create_loader(
+        self,
+        argv: list[str] | None,
+        aliases: StrDict,
+        flags: StrDict,
+        classes: ClassesType | None,
+    ) -> KVArgParseConfigLoader:
         return KVArgParseConfigLoader(
             argv, aliases, flags, classes=classes, log=self.log, subcommands=self.subcommands
         )
 
     @classmethod
-    def _get_sys_argv(cls, check_argcomplete: bool = False) -> t.List[str]:
+    def _get_sys_argv(cls, check_argcomplete: bool = False) -> list[str]:
         """Get `sys.argv` or equivalent from `argcomplete`
 
         `argcomplete`'s strategy is to call the python script with no arguments,
@@ -819,7 +817,7 @@ class Application(SingletonConfigurable):
         return sys.argv
 
     @classmethod
-    def _handle_argcomplete_for_subcommand(cls):
+    def _handle_argcomplete_for_subcommand(cls) -> None:
         """Helper for `argcomplete` to recognize `traitlets` subcommands
 
         `argcomplete` does not know that `traitlets` has already consumed subcommands,
@@ -839,7 +837,7 @@ class Application(SingletonConfigurable):
             pass
 
     @catch_config_error
-    def parse_command_line(self, argv=None):
+    def parse_command_line(self, argv: ArgvType = None) -> None:
         """Parse the command line arguments."""
         assert not isinstance(argv, str)
         if argv is None:
@@ -877,7 +875,7 @@ class Application(SingletonConfigurable):
 
         # flatten flags&aliases, so cl-args get appropriate priority:
         flags, aliases = self.flatten_flags()
-        classes = tuple(self._classes_with_config_traits())
+        classes = list(self._classes_with_config_traits())
         loader = self._create_loader(argv, aliases, flags, classes=classes)
         try:
             self.cli_config = deepcopy(loader.load_config())
@@ -890,13 +888,18 @@ class Application(SingletonConfigurable):
         self.extra_args = loader.extra_args
 
     @classmethod
-    def _load_config_files(cls, basefilename, path=None, log=None, raise_config_file_errors=False):
+    def _load_config_files(
+        cls,
+        basefilename: str,
+        path: str | t.Sequence[str | None] | None,
+        log: AnyLogger | None = None,
+        raise_config_file_errors: bool = False,
+    ) -> t.Generator[t.Any, None, None]:
         """Load config files (py,json) by filename and path.
 
         yield each config object in turn.
         """
-
-        if not isinstance(path, list):
+        if isinstance(path, str) or path is None:
             path = [path]
         for current in reversed(path):
             # path list is in descending priority order, so load files backwards:
@@ -904,8 +907,8 @@ class Application(SingletonConfigurable):
             if log:
                 log.debug("Looking for %s in %s", basefilename, current or os.getcwd())
             jsonloader = cls.json_config_loader_class(basefilename + ".json", path=current, log=log)
-            loaded: t.List[t.Any] = []
-            filenames: t.List[str] = []
+            loaded: list[t.Any] = []
+            filenames: list[str] = []
             for loader in [pyloader, jsonloader]:
                 config = None
                 try:
@@ -941,12 +944,14 @@ class Application(SingletonConfigurable):
                     filenames.append(loader.full_filename)
 
     @property
-    def loaded_config_files(self):
+    def loaded_config_files(self) -> list[str]:
         """Currently loaded configuration files"""
         return self._loaded_config_files[:]
 
     @catch_config_error
-    def load_config_file(self, filename, path=None):
+    def load_config_file(
+        self, filename: str, path: str | t.Sequence[str | None] | None = None
+    ) -> None:
         """Load config files by filename and path."""
         filename, ext = os.path.splitext(filename)
         new_config = Config()
@@ -965,7 +970,9 @@ class Application(SingletonConfigurable):
         new_config.merge(self.cli_config)
         self.update_config(new_config)
 
-    def _classes_with_config_traits(self, classes=None):
+    def _classes_with_config_traits(
+        self, classes: ClassesType | None = None
+    ) -> t.Generator[type[Configurable], None, None]:
         """
         Yields only classes with configurable traits, and their subclasses.
 
@@ -987,7 +994,7 @@ class Application(SingletonConfigurable):
             for cls in self._classes_inc_parents(classes)
         )
 
-        def is_any_parent_included(cls):
+        def is_any_parent_included(cls: t.Any) -> bool:
             return any(b in cls_to_config and cls_to_config[b] for b in cls.__bases__)
 
         # Mark "empty" classes for inclusion if their parents own-traits,
@@ -1005,7 +1012,7 @@ class Application(SingletonConfigurable):
             if inc_yes:
                 yield cl
 
-    def generate_config_file(self, classes=None):
+    def generate_config_file(self, classes: ClassesType | None = None) -> str:
         """generate default config file from Configurables"""
         lines = ["# Configuration file for %s." % self.name]
         lines.append("")
@@ -1017,7 +1024,7 @@ class Application(SingletonConfigurable):
             lines.append(cls.class_config_section(config_classes))
         return "\n".join(lines)
 
-    def close_handlers(self):
+    def close_handlers(self) -> None:
         if getattr(self, "_logging_configured", False):
             # don't attempt to close handlers unless they have been opened
             # (note accessing self.log.handlers will create handlers if they
@@ -1027,16 +1034,16 @@ class Application(SingletonConfigurable):
                     handler.close()
             self._logging_configured = False
 
-    def exit(self, exit_status=0):
+    def exit(self, exit_status: int | str | None = 0) -> None:
         self.log.debug("Exiting application: %s" % self.name)
         self.close_handlers()
         sys.exit(exit_status)
 
-    def __del__(self):
+    def __del__(self) -> None:
         self.close_handlers()
 
     @classmethod
-    def launch_instance(cls, argv=None, **kwargs):
+    def launch_instance(cls, argv: ArgvType = None, **kwargs: t.Any) -> None:
         """Launch a global instance of this Application
 
         If a global instance already exists, this reinitializes and starts it
@@ -1054,7 +1061,7 @@ default_aliases = Application.aliases
 default_flags = Application.flags
 
 
-def boolean_flag(name, configurable, set_help="", unset_help=""):
+def boolean_flag(name: str, configurable: str, set_help: str = "", unset_help: str = "") -> StrDict:
     """Helper for building basic --trait, --no-trait flags.
 
     Parameters
@@ -1085,7 +1092,7 @@ def boolean_flag(name, configurable, set_help="", unset_help=""):
     return {name: (setter, set_help), "no-" + name: (unsetter, unset_help)}
 
 
-def get_config():
+def get_config() -> Config:
     """Get the config object for the global Application instance, if there is one
 
     otherwise return an empty config object
diff --git a/contrib/python/traitlets/py3/traitlets/config/argcomplete_config.py b/contrib/python/traitlets/py3/traitlets/config/argcomplete_config.py
index ee1e51b4924..82112aaf6b3 100644
--- a/contrib/python/traitlets/py3/traitlets/config/argcomplete_config.py
+++ b/contrib/python/traitlets/py3/traitlets/config/argcomplete_config.py
@@ -15,7 +15,7 @@ except ImportError:
     # This module and its utility methods are written to not crash even
     # if argcomplete is not installed.
     class StubModule:
-        def __getattr__(self, attr):
+        def __getattr__(self, attr: str) -> t.Any:
             if not attr.startswith("__"):
                 raise ModuleNotFoundError("No module named 'argcomplete'")
             raise AttributeError(f"argcomplete stub module has no attribute '{attr}'")
@@ -63,7 +63,7 @@ def get_argcomplete_cwords() -> t.Optional[t.List[str]]:
     return comp_words
 
 
-def increment_argcomplete_index():
+def increment_argcomplete_index() -> None:
     """Assumes ``$_ARGCOMPLETE`` is set and `argcomplete` is importable
 
     Increment the index pointed to by ``$_ARGCOMPLETE``, which is used to
@@ -122,7 +122,7 @@ class ExtendedCompletionFinder(CompletionFinder):
             ]
         return matched_completions
 
-    def inject_class_to_parser(self, cls):
+    def inject_class_to_parser(self, cls: t.Any) -> None:
         """Add dummy arguments to our ArgumentParser for the traits of this class
 
         The argparse-based loader currently does not actually add any class traits to
diff --git a/contrib/python/traitlets/py3/traitlets/config/configurable.py b/contrib/python/traitlets/py3/traitlets/config/configurable.py
index f448e696b8e..77b4214e452 100644
--- a/contrib/python/traitlets/py3/traitlets/config/configurable.py
+++ b/contrib/python/traitlets/py3/traitlets/config/configurable.py
@@ -2,7 +2,7 @@
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
-
+from __future__ import annotations
 
 import logging
 import typing as t
@@ -15,12 +15,14 @@ from traitlets.traitlets import (
     Dict,
     HasTraits,
     Instance,
+    TraitType,
     default,
     observe,
     observe_compat,
     validate,
 )
 from traitlets.utils import warnings
+from traitlets.utils.bunch import Bunch
 from traitlets.utils.text import indent, wrap_paragraphs
 
 from .loader import Config, DeferredConfig, LazyConfigValue, _is_section_key
@@ -29,6 +31,11 @@ from .loader import Config, DeferredConfig, LazyConfigValue, _is_section_key
 # Helper classes for Configurables
 # -----------------------------------------------------------------------------
 
+if t.TYPE_CHECKING:
+    LoggerType = t.Union[logging.Logger, logging.LoggerAdapter[t.Any]]
+else:
+    LoggerType = t.Any
+
 
 class ConfigurableError(Exception):
     pass
@@ -87,7 +94,7 @@ class Configurable(HasTraits):
         # record traits set by config
         config_override_names = set()
 
-        def notice_config_override(change):
+        def notice_config_override(change: Bunch) -> None:
             """Record traits set by both config and kwargs.
 
             They will need to be overridden again after loading config.
@@ -120,7 +127,7 @@ class Configurable(HasTraits):
     # -------------------------------------------------------------------------
 
     @classmethod
-    def section_names(cls):
+    def section_names(cls) -> list[str]:
         """return section names as a list"""
         return [
             c.__name__
@@ -128,7 +135,7 @@ class Configurable(HasTraits):
             if issubclass(c, Configurable) and issubclass(cls, c)
         ]
 
-    def _find_my_config(self, cfg):
+    def _find_my_config(self, cfg: Config) -> t.Any:
         """extract my config from a global Config object
 
         will construct a Config object of only the config values that apply to me
@@ -153,7 +160,9 @@ class Configurable(HasTraits):
                     my_config.merge(c[sname])
         return my_config
 
-    def _load_config(self, cfg, section_names=None, traits=None):
+    def _load_config(
+        self, cfg: Config, section_names: list[str] | None = None, traits: list[str] | None = None
+    ) -> None:
         """load traits from a Config object"""
 
         if traits is None:
@@ -187,7 +196,7 @@ class Configurable(HasTraits):
                         warn = self.log.warning
                     else:
 
-                        def warn(msg):
+                        def warn(msg: t.Any) -> None:
                             return warnings.warn(msg, UserWarning, stacklevel=9)
 
                     matches = get_close_matches(name, traits)
@@ -203,7 +212,7 @@ class Configurable(HasTraits):
 
     @observe("config")
     @observe_compat
-    def _config_changed(self, change):
+    def _config_changed(self, change: Bunch) -> None:
         """Update all the class traits having ``config=True`` in metadata.
 
         For any class trait with a ``config`` metadata attribute that is
@@ -219,7 +228,7 @@ class Configurable(HasTraits):
         section_names = self.section_names()
         self._load_config(change.new, traits=traits, section_names=section_names)
 
-    def update_config(self, config):
+    def update_config(self, config: Config) -> None:
         """Update config and load the new values"""
         # traitlets prior to 4.2 created a copy of self.config in order to trigger change events.
         # Some projects (IPython < 5) relied upon one side effect of this,
@@ -236,7 +245,7 @@ class Configurable(HasTraits):
         # DO NOT trigger full trait-change
 
     @classmethod
-    def class_get_help(cls, inst=None):
+    def class_get_help(cls, inst: HasTraits | None = None) -> str:
         """Get the help string for this class in ReST format.
 
         If `inst` is given, its current trait values will be used in place of
@@ -253,7 +262,12 @@ class Configurable(HasTraits):
         return "\n".join(final_help)
 
     @classmethod
-    def class_get_trait_help(cls, trait, inst=None, helptext=None):
+    def class_get_trait_help(
+        cls,
+        trait: TraitType[t.Any, t.Any],
+        inst: HasTraits | None = None,
+        helptext: str | None = None,
+    ) -> str:
         """Get the helptext string for a single trait.
 
         :param inst:
@@ -291,7 +305,7 @@ class Configurable(HasTraits):
             lines.append(indent("Choices: %s" % trait.info()))
 
         if inst is not None:
-            lines.append(indent(f"Current: {getattr(inst, trait.name)!r}"))
+            lines.append(indent(f"Current: {getattr(inst, trait.name or '')!r}"))
         else:
             try:
                 dvr = trait.default_value_repr()
@@ -305,12 +319,14 @@ class Configurable(HasTraits):
         return "\n".join(lines)
 
     @classmethod
-    def class_print_help(cls, inst=None):
+    def class_print_help(cls, inst: HasTraits | None = None) -> None:
         """Get the help string for a single trait and print it."""
         print(cls.class_get_help(inst))
 
     @classmethod
-    def _defining_class(cls, trait, classes):
+    def _defining_class(
+        cls, trait: TraitType[t.Any, t.Any], classes: t.Sequence[type[HasTraits]]
+    ) -> type[Configurable]:
         """Get the class that defines a trait
 
         For reducing redundant help output in config files.
@@ -338,7 +354,7 @@ class Configurable(HasTraits):
         return defining_cls
 
     @classmethod
-    def class_config_section(cls, classes=None):
+    def class_config_section(cls, classes: t.Sequence[type[HasTraits]] | None = None) -> str:
         """Get the config section for this class.
 
         Parameters
@@ -348,7 +364,7 @@ class Configurable(HasTraits):
             Used to reduce redundant information.
         """
 
-        def c(s):
+        def c(s: str) -> str:
             """return a commented, wrapped block."""
             s = "\n\n".join(wrap_paragraphs(s, 78))
 
@@ -398,7 +414,7 @@ class Configurable(HasTraits):
         return "\n".join(lines)
 
     @classmethod
-    def class_config_rst_doc(cls):
+    def class_config_rst_doc(cls) -> str:
         """Generate rST documentation for this class' config options.
 
         Excludes traits defined on parent classes.
@@ -447,10 +463,10 @@ class LoggingConfigurable(Configurable):
     is to get the logger from the currently running Application.
     """
 
-    log = Any(help="Logger or LoggerAdapter instance")
+    log = Any(help="Logger or LoggerAdapter instance", allow_none=False)
 
     @validate("log")
-    def _validate_log(self, proposal):
+    def _validate_log(self, proposal: Bunch) -> LoggerType:
         if not isinstance(proposal.value, (logging.Logger, logging.LoggerAdapter)):
             # warn about unsupported type, but be lenient to allow for duck typing
             warnings.warn(
@@ -459,18 +475,18 @@ class LoggingConfigurable(Configurable):
                 UserWarning,
                 stacklevel=2,
             )
-        return proposal.value
+        return proposal.value  # type:ignore[no-any-return]
 
     @default("log")
-    def _log_default(self):
+    def _log_default(self) -> LoggerType:
         if isinstance(self.parent, LoggingConfigurable):
             assert self.parent is not None
-            return self.parent.log
+            return t.cast(logging.Logger, self.parent.log)
         from traitlets import log
 
         return log.get_logger()
 
-    def _get_log_handler(self):
+    def _get_log_handler(self) -> logging.Handler | None:
         """Return the default Handler
 
         Returns None if none can be found
@@ -478,13 +494,16 @@ class LoggingConfigurable(Configurable):
         Deprecated, this now returns the first log handler which may or may
         not be the default one.
         """
-        logger = self.log
-        if isinstance(logger, logging.LoggerAdapter):
-            logger = logger.logger
+        if not self.log:
+            return None
+        logger = self.log if isinstance(self.log, logging.Logger) else self.log.logger
         if not getattr(logger, "handlers", None):
             # no handlers attribute or empty handlers list
             return None
-        return logger.handlers[0]
+        return logger.handlers[0]  # type:ignore[no-any-return]
+
+
+CT = t.TypeVar('CT', bound='SingletonConfigurable')
 
 
 class SingletonConfigurable(LoggingConfigurable):
@@ -498,7 +517,7 @@ class SingletonConfigurable(LoggingConfigurable):
     _instance = None
 
     @classmethod
-    def _walk_mro(cls):
+    def _walk_mro(cls) -> t.Generator[type[SingletonConfigurable], None, None]:
         """Walk the cls.mro() for parent classes that are also singletons
 
         For use in instance()
@@ -513,7 +532,7 @@ class SingletonConfigurable(LoggingConfigurable):
                 yield subclass
 
     @classmethod
-    def clear_instance(cls):
+    def clear_instance(cls) -> None:
         """unset _instance for this class and singleton parents."""
         if not cls.initialized():
             return
@@ -524,7 +543,7 @@ class SingletonConfigurable(LoggingConfigurable):
                 subclass._instance = None
 
     @classmethod
-    def instance(cls, *args, **kwargs):
+    def instance(cls: type[CT], *args: t.Any, **kwargs: t.Any) -> CT:
         """Returns a global instance of this class.
 
         This method create a new instance if none have previously been created
@@ -568,6 +587,6 @@ class SingletonConfigurable(LoggingConfigurable):
             )
 
     @classmethod
-    def initialized(cls):
+    def initialized(cls) -> bool:
         """Has an instance been created?"""
         return hasattr(cls, "_instance") and cls._instance is not None
diff --git a/contrib/python/traitlets/py3/traitlets/config/loader.py b/contrib/python/traitlets/py3/traitlets/config/loader.py
index 34d62e5a502..437c8c17cda 100644
--- a/contrib/python/traitlets/py3/traitlets/config/loader.py
+++ b/contrib/python/traitlets/py3/traitlets/config/loader.py
@@ -2,6 +2,7 @@
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
+# ruff: noqa: ANN201, ANN001, ANN204, ANN102, ANN003, ANN206, ANN002
 from __future__ import annotations
 
 import argparse
@@ -50,10 +51,10 @@ class ArgumentError(ConfigLoaderError):
 
 
 class _Sentinel:
-    def __repr__(self):
+    def __repr__(self) -> str:
         return "<Sentinel deprecated>"
 
-    def __str__(self):
+    def __str__(self) -> str:
         return "<deprecated>"
 
 
@@ -208,7 +209,7 @@ class LazyConfigValue(HasTraits):
             d["inserts"] = self._inserts
         return d
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         if self._value is not None:
             return f"<{self.__class__.__name__} value={self._value!r}>"
         else:
@@ -294,7 +295,7 @@ class Config(dict):  # type:ignore[type-arg]
                     collisions[section][key] = f"{mine[key]!r} ignored, using {theirs[key]!r}"
         return collisions
 
-    def __contains__(self, key):
+    def __contains__(self, key: t.Any) -> bool:
         # allow nested contains of the form `"Section.key" in config`
         if "." in key:
             first, remainder = key.split(".", 1)
@@ -344,7 +345,7 @@ class Config(dict):  # type:ignore[type-arg]
             else:
                 raise
 
-    def __setitem__(self, key, value):
+    def __setitem__(self, key: str, value: t.Any) -> None:
         if _is_section_key(key):
             if not isinstance(value, Config):
                 raise ValueError(
@@ -361,7 +362,7 @@ class Config(dict):  # type:ignore[type-arg]
         except KeyError as e:
             raise AttributeError(e) from e
 
-    def __setattr__(self, key, value):
+    def __setattr__(self, key: str, value: t.Any) -> None:
         if key.startswith("__"):
             return dict.__setattr__(self, key, value)
         try:
@@ -369,7 +370,7 @@ class Config(dict):  # type:ignore[type-arg]
         except KeyError as e:
             raise AttributeError(e) from e
 
-    def __delattr__(self, key):
+    def __delattr__(self, key: str) -> None:
         if key.startswith("__"):
             return dict.__delattr__(self, key)
         try:
@@ -420,7 +421,7 @@ class DeferredConfigString(str, DeferredConfig):
             # this will raise a more informative error when config is loaded.
             return s
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return f"{self.__class__.__name__}({self._super_repr()})"
 
 
@@ -462,7 +463,7 @@ class DeferredConfigList(list, DeferredConfig):  # type:ignore[type-arg]
             # this will raise a more informative error when config is loaded.
             return src
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return f"{self.__class__.__name__}({self._super_repr()})"
 
 
@@ -749,7 +750,7 @@ class _DefaultOptionDict(dict):  # type:ignore[type-arg]
             metavar=key.lstrip("-"),
         )
 
-    def __contains__(self, key):
+    def __contains__(self, key: t.Any) -> bool:
         if "=" in key:
             return False
         if super().__contains__(key):
@@ -785,7 +786,6 @@ class _KVArgParser(argparse.ArgumentParser):
 
 
 # type aliases
-Flags = t.Union[str, t.Tuple[str, ...]]
 SubcommandsDict = t.Dict[str, t.Any]
 
 
@@ -797,8 +797,8 @@ class ArgParseConfigLoader(CommandLineConfigLoader):
     def __init__(
         self,
         argv: list[str] | None = None,
-        aliases: dict[Flags, str] | None = None,
-        flags: dict[Flags, str] | None = None,
+        aliases: dict[str, str] | None = None,
+        flags: dict[str, str] | None = None,
         log: t.Any = None,
         classes: list[type[t.Any]] | None = None,
         subcommands: SubcommandsDict | None = None,
@@ -915,7 +915,7 @@ class ArgParseConfigLoader(CommandLineConfigLoader):
                 if alias in self.flags:
                     continue
                 if not isinstance(alias, tuple):
-                    alias = (alias,)
+                    alias = (alias,)  # type:ignore[assignment]
                 for al in alias:
                     if len(al) == 1:
                         unpacked_aliases["-" + al] = "--" + alias_target
diff --git a/contrib/python/traitlets/py3/traitlets/config/manager.py b/contrib/python/traitlets/py3/traitlets/config/manager.py
index 728cd2f22cc..9102544e509 100644
--- a/contrib/python/traitlets/py3/traitlets/config/manager.py
+++ b/contrib/python/traitlets/py3/traitlets/config/manager.py
@@ -2,15 +2,18 @@
 """
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
+from __future__ import annotations
+
 import errno
 import json
 import os
+from typing import Any
 
 from traitlets.config import LoggingConfigurable
 from traitlets.traitlets import Unicode
 
 
-def recursive_update(target, new):
+def recursive_update(target: dict[Any, Any], new: dict[Any, Any]) -> None:
     """Recursively update one dictionary using another.
 
     None values will delete their keys.
@@ -39,17 +42,17 @@ class BaseJSONConfigManager(LoggingConfigurable):
 
     config_dir = Unicode(".")
 
-    def ensure_config_dir_exists(self):
+    def ensure_config_dir_exists(self) -> None:
         try:
             os.makedirs(self.config_dir, 0o755)
         except OSError as e:
             if e.errno != errno.EEXIST:
                 raise
 
-    def file_name(self, section_name):
+    def file_name(self, section_name: str) -> str:
         return os.path.join(self.config_dir, section_name + ".json")
 
-    def get(self, section_name):
+    def get(self, section_name: str) -> Any:
         """Retrieve the config data for the specified section.
 
         Returns the data as a dictionary, or an empty dictionary if the file
@@ -62,7 +65,7 @@ class BaseJSONConfigManager(LoggingConfigurable):
         else:
             return {}
 
-    def set(self, section_name, data):
+    def set(self, section_name: str, data: Any) -> None:
         """Store the given config data."""
         filename = self.file_name(section_name)
         self.ensure_config_dir_exists()
@@ -71,7 +74,7 @@ class BaseJSONConfigManager(LoggingConfigurable):
         with f:
             json.dump(data, f, indent=2)
 
-    def update(self, section_name, new_data):
+    def update(self, section_name: str, new_data: Any) -> Any:
         """Modify the config section by recursively updating it with new_data.
 
         Returns the modified config data as a dictionary.
diff --git a/contrib/python/traitlets/py3/traitlets/config/sphinxdoc.py b/contrib/python/traitlets/py3/traitlets/config/sphinxdoc.py
index a69d89f9e48..300c0a0b03d 100644
--- a/contrib/python/traitlets/py3/traitlets/config/sphinxdoc.py
+++ b/contrib/python/traitlets/py3/traitlets/config/sphinxdoc.py
@@ -32,6 +32,7 @@ The generated rST syntax looks like this::
 
     Cross reference like this: :configtrait:`Application.log_datefmt`.
 """
+# ruff: noqa: ANN201, ANN001, ANN204, ANN102, ANN003, ANN206, ANN002
 from collections import defaultdict
 from textwrap import dedent
 
diff --git a/contrib/python/traitlets/py3/traitlets/log.py b/contrib/python/traitlets/py3/traitlets/log.py
index 468c7c3c24e..d90a9c5284c 100644
--- a/contrib/python/traitlets/py3/traitlets/log.py
+++ b/contrib/python/traitlets/py3/traitlets/log.py
@@ -5,11 +5,12 @@
 from __future__ import annotations
 
 import logging
+from typing import Any
 
-_logger: logging.Logger | None = None
+_logger: logging.Logger | logging.LoggerAdapter[Any] | None = None
 
 
-def get_logger() -> logging.Logger:
+def get_logger() -> logging.Logger | logging.LoggerAdapter[Any]:
     """Grab the global logger instance.
 
     If a global Application is instantiated, grab its logger.
diff --git a/contrib/python/traitlets/py3/traitlets/tests/utils.py b/contrib/python/traitlets/py3/traitlets/tests/utils.py
index c39d86942a5..9552a5c786c 100644
--- a/contrib/python/traitlets/py3/traitlets/tests/utils.py
+++ b/contrib/python/traitlets/py3/traitlets/tests/utils.py
@@ -1,20 +1,23 @@
+from __future__ import annotations
+
 import sys
 from subprocess import PIPE, Popen
-import os
+from typing import Any, Sequence
 
 
-def get_output_error_code(cmd):
+def get_output_error_code(cmd: str | Sequence[str]) -> tuple[str, str, Any]:
     """Get stdout, stderr, and exit code from running a command"""
+    import os
     env = os.environ.copy()
     env["Y_PYTHON_ENTRY_POINT"] = ":main"
     p = Popen(cmd, stdout=PIPE, stderr=PIPE, env=env)  # noqa
     out, err = p.communicate()
-    out = out.decode("utf8", "replace")  # type:ignore
-    err = err.decode("utf8", "replace")  # type:ignore
-    return out, err, p.returncode
+    out_str = out.decode("utf8", "replace")
+    err_str = err.decode("utf8", "replace")
+    return out_str, err_str, p.returncode
 
 
-def check_help_output(pkg, subcommand=None):
+def check_help_output(pkg: str, subcommand: Sequence[str] | None = None) -> tuple[str, str]:
     """test that `python -m PKG [subcommand] -h` works"""
     cmd = [sys.executable, "-m", pkg]
     if subcommand:
@@ -28,7 +31,7 @@ def check_help_output(pkg, subcommand=None):
     return out, err
 
 
-def check_help_all_output(pkg, subcommand=None):
+def check_help_all_output(pkg: str, subcommand: Sequence[str] | None = None) -> tuple[str, str]:
     """test that `python -m PKG --help-all` works"""
     cmd = [sys.executable, "-m", pkg]
     if subcommand:
diff --git a/contrib/python/traitlets/py3/traitlets/traitlets.py b/contrib/python/traitlets/py3/traitlets/traitlets.py
index 036f51aac1d..50d6face52e 100644
--- a/contrib/python/traitlets/py3/traitlets/traitlets.py
+++ b/contrib/python/traitlets/py3/traitlets/traitlets.py
@@ -38,6 +38,9 @@ Inheritance diagram:
 #
 # Adapted from enthought.traits, Copyright (c) Enthought, Inc.,
 # also under the terms of the Modified BSD License.
+
+# ruff: noqa: ANN001, ANN204, ANN201, ANN003, ANN206, ANN002
+
 from __future__ import annotations
 
 import contextlib
@@ -213,16 +216,16 @@ def parse_notifier_name(names: Sentinel | str | t.Iterable[Sentinel | str]) -> t
 
 
 class _SimpleTest:
-    def __init__(self, value):
+    def __init__(self, value: t.Any) -> None:
         self.value = value
 
-    def __call__(self, test):
-        return test == self.value
+    def __call__(self, test: t.Any) -> bool:
+        return bool(test == self.value)
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return "<SimpleTest(%r)" % self.value
 
-    def __str__(self):
+    def __str__(self) -> str:
         return self.__repr__()
 
 
@@ -294,7 +297,7 @@ class link:
 
         self.link()
 
-    def link(self):
+    def link(self) -> None:
         try:
             setattr(
                 self.target[0],
@@ -334,7 +337,7 @@ class link:
                     f"Broken link {self}: the target value changed while updating " "the source."
                 )
 
-    def unlink(self):
+    def unlink(self) -> None:
         self.source[0].unobserve(self._update_target, names=self.source[1])
         self.target[0].unobserve(self._update_source, names=self.target[1])
 
@@ -378,7 +381,7 @@ class directional_link:
         self.source, self.target = source, target
         self.link()
 
-    def link(self):
+    def link(self) -> None:
         try:
             setattr(
                 self.target[0],
@@ -402,7 +405,7 @@ class directional_link:
         with self._busy_updating():
             setattr(self.target[0], self.target[1], self._transform(change.new))
 
-    def unlink(self):
+    def unlink(self) -> None:
         self.source[0].unobserve(self._update, names=self.source[1])
 
 
@@ -1123,7 +1126,7 @@ def observe(*names: Sentinel | str, type: str = "change") -> ObserveHandler:
     return ObserveHandler(names, type=type)
 
 
-def observe_compat(func):
+def observe_compat(func: FuncT) -> FuncT:
     """Backward-compatibility shim decorator for observers
 
     Use with:
@@ -1137,9 +1140,11 @@ def observe_compat(func):
     Allows adoption of new observer API without breaking subclasses that override and super.
     """
 
-    def compatible_observer(self, change_or_name, old=Undefined, new=Undefined):
+    def compatible_observer(
+        self: t.Any, change_or_name: str, old: t.Any = Undefined, new: t.Any = Undefined
+    ) -> t.Any:
         if isinstance(change_or_name, dict):
-            change = change_or_name
+            change = Bunch(change_or_name)
         else:
             clsname = self.__class__.__name__
             warn(
@@ -1156,7 +1161,7 @@ def observe_compat(func):
             )
         return func(self, change)
 
-    return compatible_observer
+    return t.cast(FuncT, compatible_observer)
 
 
 def validate(*names: Sentinel | str) -> ValidateHandler:
@@ -2027,7 +2032,7 @@ class Type(ClassBasedTraitType[G, S]):
 
         @t.overload
         def __init__(
-            self: Type[object, object],
+            self: Type[type, type],
             default_value: Sentinel | None | str = ...,
             klass: None | str = ...,
             allow_none: Literal[False] = ...,
@@ -2040,8 +2045,8 @@ class Type(ClassBasedTraitType[G, S]):
 
         @t.overload
         def __init__(
-            self: Type[object | None, object | None],
-            default_value: S | Sentinel | None | str = ...,
+            self: Type[type | None, type | None],
+            default_value: Sentinel | None | str = ...,
             klass: None | str = ...,
             allow_none: Literal[True] = ...,
             read_only: bool | None = ...,
@@ -2054,7 +2059,7 @@ class Type(ClassBasedTraitType[G, S]):
         @t.overload
         def __init__(
             self: Type[S, S],
-            default_value: S | Sentinel | str = ...,
+            default_value: S = ...,
             klass: type[S] = ...,
             allow_none: Literal[False] = ...,
             read_only: bool | None = ...,
@@ -2067,7 +2072,7 @@ class Type(ClassBasedTraitType[G, S]):
         @t.overload
         def __init__(
             self: Type[S | None, S | None],
-            default_value: S | Sentinel | None | str = ...,
+            default_value: S | None = ...,
             klass: type[S] = ...,
             allow_none: Literal[True] = ...,
             read_only: bool | None = ...,
diff --git a/contrib/python/traitlets/py3/traitlets/utils/__init__.py b/contrib/python/traitlets/py3/traitlets/utils/__init__.py
index dfec4ee322e..e8ee7f98561 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/__init__.py
+++ b/contrib/python/traitlets/py3/traitlets/utils/__init__.py
@@ -1,15 +1,18 @@
+from __future__ import annotations
+
 import os
 import pathlib
+from typing import Sequence
 
 
 # vestigal things from IPython_genutils.
-def cast_unicode(s, encoding="utf-8"):
+def cast_unicode(s: str | bytes, encoding: str = "utf-8") -> str:
     if isinstance(s, bytes):
         return s.decode(encoding, "replace")
     return s
 
 
-def filefind(filename, path_dirs=None):
+def filefind(filename: str, path_dirs: Sequence[str] | None = None) -> str:
     """Find a file by looking through a sequence of paths.
 
     This iterates through a sequence of paths looking for a file and returns
@@ -65,7 +68,7 @@ def filefind(filename, path_dirs=None):
     raise OSError(f"File {filename!r} does not exist in any of the search paths: {path_dirs!r}")
 
 
-def expand_path(s):
+def expand_path(s: str) -> str:
     """Expand $VARS and ~names in a string, like a shell
 
     :Examples:
diff --git a/contrib/python/traitlets/py3/traitlets/utils/bunch.py b/contrib/python/traitlets/py3/traitlets/utils/bunch.py
index 6b3fffeb12a..498563e0b5b 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/bunch.py
+++ b/contrib/python/traitlets/py3/traitlets/utils/bunch.py
@@ -5,21 +5,24 @@ attribute-access of items on a dict.
 
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
+from __future__ import annotations
+
+from typing import Any
 
 
 class Bunch(dict):  # type:ignore[type-arg]
     """A dict with attribute-access"""
 
-    def __getattr__(self, key):
+    def __getattr__(self, key: str) -> Any:
         try:
             return self.__getitem__(key)
         except KeyError as e:
             raise AttributeError(key) from e
 
-    def __setattr__(self, key, value):
+    def __setattr__(self, key: str, value: Any) -> None:
         self.__setitem__(key, value)
 
-    def __dir__(self):
+    def __dir__(self) -> list[str]:
         # py2-compat: can't use super because dict doesn't have __dir__
         names = dir({})
         names.extend(self.keys())
diff --git a/contrib/python/traitlets/py3/traitlets/utils/decorators.py b/contrib/python/traitlets/py3/traitlets/utils/decorators.py
index a59e8167b0a..dedbaad193f 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/decorators.py
+++ b/contrib/python/traitlets/py3/traitlets/utils/decorators.py
@@ -2,12 +2,12 @@
 
 import copy
 from inspect import Parameter, Signature, signature
-from typing import Type, TypeVar
+from typing import Any, Type, TypeVar
 
 from ..traitlets import HasTraits, Undefined
 
 
-def _get_default(value):
+def _get_default(value: Any) -> Any:
     """Get default argument value, given the trait default value."""
     return Parameter.empty if value == Undefined else value
 
diff --git a/contrib/python/traitlets/py3/traitlets/utils/descriptions.py b/contrib/python/traitlets/py3/traitlets/utils/descriptions.py
index 232eb0e728b..c068ecdba5a 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/descriptions.py
+++ b/contrib/python/traitlets/py3/traitlets/utils/descriptions.py
@@ -1,9 +1,18 @@
+from __future__ import annotations
+
 import inspect
 import re
 import types
+from typing import Any
 
 
-def describe(article, value, name=None, verbose=False, capital=False):
+def describe(
+    article: str | None,
+    value: Any,
+    name: str | None = None,
+    verbose: bool = False,
+    capital: bool = False,
+) -> str:
     """Return string that describes a value
 
     Parameters
@@ -110,7 +119,7 @@ def describe(article, value, name=None, verbose=False, capital=False):
         )
 
 
-def _prefix(value):
+def _prefix(value: Any) -> str:
     if isinstance(value, types.MethodType):
         name = describe(None, value.__self__, verbose=True) + "."
     else:
@@ -122,7 +131,7 @@ def _prefix(value):
     return name
 
 
-def class_of(value):
+def class_of(value: Any) -> Any:
     """Returns a string of the value's type with an indefinite article.
 
     For example 'an Image' or 'a PlotValue'.
@@ -133,7 +142,7 @@ def class_of(value):
         return class_of(type(value))
 
 
-def add_article(name, definite=False, capital=False):
+def add_article(name: str, definite: bool = False, capital: bool = False) -> str:
     """Returns the string with a prepended article.
 
     The input does not need to begin with a charater.
@@ -164,7 +173,7 @@ def add_article(name, definite=False, capital=False):
         return result
 
 
-def repr_type(obj):
+def repr_type(obj: Any) -> str:
     """Return a string representation of a value and its type for readable
 
     error messages.
diff --git a/contrib/python/traitlets/py3/traitlets/utils/getargspec.py b/contrib/python/traitlets/py3/traitlets/utils/getargspec.py
index e2b1f235c83..7cbc82659c4 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/getargspec.py
+++ b/contrib/python/traitlets/py3/traitlets/utils/getargspec.py
@@ -7,14 +7,14 @@
     :copyright: Copyright 2007-2015 by the Sphinx team, see AUTHORS.
     :license: BSD, see LICENSE for details.
 """
-
 import inspect
 from functools import partial
+from typing import Any
 
 # Unmodified from sphinx below this line
 
 
-def getargspec(func):
+def getargspec(func: Any) -> inspect.FullArgSpec:
     """Like inspect.getargspec but supports functools.partial as well."""
     if inspect.ismethod(func):
         func = func.__func__
diff --git a/contrib/python/traitlets/py3/traitlets/utils/nested_update.py b/contrib/python/traitlets/py3/traitlets/utils/nested_update.py
index 7f09e171a31..37e2d27cd20 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/nested_update.py
+++ b/contrib/python/traitlets/py3/traitlets/utils/nested_update.py
@@ -1,8 +1,9 @@
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
+from typing import Any, Dict
 
 
-def nested_update(this, that):
+def nested_update(this: Dict[Any, Any], that: Dict[Any, Any]) -> Dict[Any, Any]:
     """Merge two nested dictionaries.
 
     Effectively a recursive ``dict.update``.
diff --git a/contrib/python/traitlets/py3/traitlets/utils/text.py b/contrib/python/traitlets/py3/traitlets/utils/text.py
index c7d49edece6..72ad98fc2ae 100644
--- a/contrib/python/traitlets/py3/traitlets/utils/text.py
+++ b/contrib/python/traitlets/py3/traitlets/utils/text.py
@@ -9,7 +9,7 @@ from textwrap import indent as _indent
 from typing import List
 
 
-def indent(val):
+def indent(val: str) -> str:
     res = _indent(val, "    ")
     return res
 
diff --git a/contrib/python/traitlets/py3/ya.make b/contrib/python/traitlets/py3/ya.make
index 2d9cfeae1b0..ff8ebca152a 100644
--- a/contrib/python/traitlets/py3/ya.make
+++ b/contrib/python/traitlets/py3/ya.make
@@ -4,7 +4,7 @@ PY3_LIBRARY()
 
 PROVIDES(python_traitlets)
 
-VERSION(5.10.1)
+VERSION(5.11.2)
 
 LICENSE(BSD-3-Clause)
 
@@ -23,7 +23,6 @@ PY_SRCS(
     traitlets/config/sphinxdoc.py
     traitlets/log.py
     traitlets/tests/__init__.py
-    traitlets/tests/_warnings.py
     traitlets/tests/utils.py
     traitlets/traitlets.py
     traitlets/utils/__init__.py