YT-19324: move YT provider to ydb/library/yql

This commit is formed by the following script: https://paste.yandex-team.ru/6f92e4b8-efc5-4d34-948b-15ee2accd7e7/text.
This commit has zero effect on all projects that depend on YQL.

The summary of changes:
- `yql/providers/yt -> ydb/library/yql/providers/yt `- the whole implementation of YT provider is moved into YDB code base for further export as a part of YT YQL plugin shared library;
- `yql/providers/stat/{expr_nodes,uploader} -> ydb/library/yql/providers/stat/{expr_nodes,uploader}` - a small interface without implementation and the description of stat expr nodes;
- `yql/core/extract_predicate/ut -> ydb/library/yql/core/extract_predicate/ut`;
- `yql/core/{ut,ut_common} -> ydb/library/yql/core/{ut,ut_common}`;
- `yql/core` is gone;
- `yql/library/url_preprocessing -> ydb/library/yql/core/url_preprocessing`.

**NB**: all new targets inside `ydb/` are under `IF (NOT CMAKE_EXPORT)` clause which disables them from open-source cmake generation and ya make build. They will be enabled in the subsequent commits.

1 files changed, 1782 insertions, 0 deletions

diff --git a/contrib/libs/flatbuffers/src/idl_gen_python.cpp b/contrib/libs/flatbuffers/src/idl_gen_python.cpp
new file mode 100644
index 0000000000..b3f394ebf9
--- /dev/null
+++ b/contrib/libs/flatbuffers/src/idl_gen_python.cpp
@@ -0,0 +1,1782 @@
+/*
+ * Copyright 2014 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// independent from idl_parser, since this code is not needed for most clients
+
+#include <cctype>
+#include <set>
+#include <string>
+#include <unordered_set>
+#include <vector>
+
+#include "flatbuffers/code_generators.h"
+#include "flatbuffers/flatbuffers.h"
+#include "flatbuffers/idl.h"
+#include "flatbuffers/util.h"
+
+namespace flatbuffers {
+namespace python {
+
+// Hardcode spaces per indentation.
+const CommentConfig def_comment = { nullptr, "#", nullptr };
+const std::string Indent = "    ";
+
+class PythonGenerator : public BaseGenerator {
+ public:
+  PythonGenerator(const Parser &parser, const std::string &path,
+                  const std::string &file_name)
+      : BaseGenerator(parser, path, file_name, "" /* not used */,
+                      "" /* not used */, "py"),
+        float_const_gen_("float('nan')", "float('inf')", "float('-inf')") {
+    static const char *const keywords[] = {
+      "False",   "None",     "True",     "and",    "as",   "assert", "break",
+      "class",   "continue", "def",      "del",    "elif", "else",   "except",
+      "finally", "for",      "from",     "global", "if",   "import", "in",
+      "is",      "lambda",   "nonlocal", "not",    "or",   "pass",   "raise",
+      "return",  "try",      "while",    "with",   "yield"
+    };
+    keywords_.insert(std::begin(keywords), std::end(keywords));
+  }
+
+  // Most field accessors need to retrieve and test the field offset first,
+  // this is the prefix code for that.
+  std::string OffsetPrefix(const FieldDef &field) {
+    return "\n" + Indent + Indent +
+           "o = flatbuffers.number_types.UOffsetTFlags.py_type" +
+           "(self._tab.Offset(" + NumToString(field.value.offset) + "))\n" +
+           Indent + Indent + "if o != 0:\n";
+  }
+
+  // Begin a class declaration.
+  void BeginClass(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "class " + NormalizedName(struct_def) + "(object):\n";
+    code += Indent + "__slots__ = ['_tab']";
+    code += "\n\n";
+  }
+
+  // Begin enum code with a class declaration.
+  void BeginEnum(const std::string &class_name, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "class " + class_name + "(object):\n";
+  }
+
+  std::string EscapeKeyword(const std::string &name) const {
+    return keywords_.find(name) == keywords_.end() ? name : name + "_";
+  }
+
+  std::string NormalizedName(const Definition &definition) const {
+    return EscapeKeyword(definition.name);
+  }
+
+  std::string NormalizedName(const EnumVal &ev) const {
+    return EscapeKeyword(ev.name);
+  }
+
+  // Converts the name of a definition into upper Camel format.
+  std::string MakeUpperCamel(const Definition &definition) const {
+    return MakeCamel(NormalizedName(definition), true);
+  }
+
+  // Converts the name of a definition into lower Camel format.
+  std::string MakeLowerCamel(const Definition &definition) const {
+    auto name = MakeCamel(NormalizedName(definition), false);
+    name[0] = CharToLower(name[0]);
+    return name;
+  }
+
+  // Starts a new line and then indents.
+  std::string GenIndents(int num) {
+    return "\n" + std::string(num * Indent.length(), ' ');
+  }
+
+  // A single enum member.
+  void EnumMember(const EnumDef &enum_def, const EnumVal &ev,
+                  std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += Indent;
+    code += NormalizedName(ev);
+    code += " = ";
+    code += enum_def.ToString(ev) + "\n";
+  }
+
+  // End enum code.
+  void EndEnum(std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "\n";
+  }
+
+  // Initialize a new struct or table from existing data.
+  void NewRootTypeFromBuffer(const StructDef &struct_def,
+                             std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    code += Indent + "@classmethod\n";
+    code += Indent + "def GetRootAs";
+    code += "(cls, buf, offset=0):";
+    code += "\n";
+    code += Indent + Indent;
+    code += "n = flatbuffers.encode.Get";
+    code += "(flatbuffers.packer.uoffset, buf, offset)\n";
+    code += Indent + Indent + "x = " + NormalizedName(struct_def) + "()\n";
+    code += Indent + Indent + "x.Init(buf, n + offset)\n";
+    code += Indent + Indent + "return x\n";
+    code += "\n";
+
+    // Add an alias with the old name
+    code += Indent + "@classmethod\n";
+    code += Indent + "def GetRootAs";
+    code += NormalizedName(struct_def);
+    code += "(cls, buf, offset=0):\n";
+    code += Indent + Indent + "\"\"\"This method is deprecated. Please switch to GetRootAs.\"\"\"\n";
+    code += Indent + Indent + "return cls.GetRootAs(buf, offset)\n";
+  }
+
+  // Initialize an existing object with other data, to avoid an allocation.
+  void InitializeExisting(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    GenReceiver(struct_def, code_ptr);
+    code += "Init(self, buf, pos):\n";
+    code += Indent + Indent + "self._tab = flatbuffers.table.Table(buf, pos)\n";
+    code += "\n";
+  }
+
+  // Get the length of a vector.
+  void GetVectorLen(const StructDef &struct_def, const FieldDef &field,
+                    std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field)) + "Length(self";
+    code += "):" + OffsetPrefix(field);
+    code += Indent + Indent + Indent + "return self._tab.VectorLen(o)\n";
+    code += Indent + Indent + "return 0\n\n";
+  }
+
+  // Determines whether a vector is none or not.
+  void GetVectorIsNone(const StructDef &struct_def, const FieldDef &field,
+                       std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field)) + "IsNone(self";
+    code += "):";
+    code += GenIndents(2) +
+            "o = flatbuffers.number_types.UOffsetTFlags.py_type" +
+            "(self._tab.Offset(" + NumToString(field.value.offset) + "))";
+    code += GenIndents(2) + "return o == 0";
+    code += "\n\n";
+  }
+
+  // Get the value of a struct's scalar.
+  void GetScalarFieldOfStruct(const StructDef &struct_def,
+                              const FieldDef &field, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    std::string getter = GenGetter(field.value.type);
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    code += "(self): return " + getter;
+    code += "self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(";
+    code += NumToString(field.value.offset) + "))\n";
+  }
+
+  // Get the value of a table's scalar.
+  void GetScalarFieldOfTable(const StructDef &struct_def, const FieldDef &field,
+                             std::string *code_ptr) {
+    auto &code = *code_ptr;
+    std::string getter = GenGetter(field.value.type);
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    code += "(self):";
+    code += OffsetPrefix(field);
+    getter += "o + self._tab.Pos)";
+    auto is_bool = IsBool(field.value.type.base_type);
+    if (is_bool) { getter = "bool(" + getter + ")"; }
+    code += Indent + Indent + Indent + "return " + getter + "\n";
+    std::string default_value;
+    if (is_bool) {
+      default_value = field.value.constant == "0" ? "False" : "True";
+    } else {
+      default_value = IsFloat(field.value.type.base_type)
+                          ? float_const_gen_.GenFloatConstant(field)
+                          : field.value.constant;
+    }
+    code += Indent + Indent + "return " + default_value + "\n\n";
+  }
+
+  // Get a struct by initializing an existing struct.
+  // Specific to Struct.
+  void GetStructFieldOfStruct(const StructDef &struct_def,
+                              const FieldDef &field, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    code += "(self, obj):\n";
+    code += Indent + Indent + "obj.Init(self._tab.Bytes, self._tab.Pos + ";
+    code += NumToString(field.value.offset) + ")";
+    code += "\n" + Indent + Indent + "return obj\n\n";
+  }
+
+  // Get the value of a fixed size array.
+  void GetArrayOfStruct(const StructDef &struct_def, const FieldDef &field,
+                        std::string *code_ptr) {
+    auto &code = *code_ptr;
+    const auto vec_type = field.value.type.VectorType();
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    if (IsStruct(vec_type)) {
+      code += "(self, obj, i):\n";
+      code += Indent + Indent + "obj.Init(self._tab.Bytes, self._tab.Pos + ";
+      code += NumToString(field.value.offset) + " + i * ";
+      code += NumToString(InlineSize(vec_type));
+      code += ")\n" + Indent + Indent + "return obj\n\n";
+    } else {
+      auto getter = GenGetter(vec_type);
+      code += "(self): return [" + getter;
+      code += "self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(";
+      code += NumToString(field.value.offset) + " + i * ";
+      code += NumToString(InlineSize(vec_type));
+      code += ")) for i in range(";
+      code += NumToString(field.value.type.fixed_length) + ")]\n";
+    }
+  }
+
+  // Get a struct by initializing an existing struct.
+  // Specific to Table.
+  void GetStructFieldOfTable(const StructDef &struct_def, const FieldDef &field,
+                             std::string *code_ptr) {
+    auto &code = *code_ptr;
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    code += "(self):";
+    code += OffsetPrefix(field);
+    if (field.value.type.struct_def->fixed) {
+      code += Indent + Indent + Indent + "x = o + self._tab.Pos\n";
+    } else {
+      code += Indent + Indent + Indent;
+      code += "x = self._tab.Indirect(o + self._tab.Pos)\n";
+    }
+    if (parser_.opts.include_dependence_headers) {
+      code += Indent + Indent + Indent;
+      code += "from " + GenPackageReference(field.value.type) + " import " +
+              TypeName(field) + "\n";
+    }
+    code += Indent + Indent + Indent + "obj = " + TypeName(field) + "()\n";
+    code += Indent + Indent + Indent + "obj.Init(self._tab.Bytes, x)\n";
+    code += Indent + Indent + Indent + "return obj\n";
+    code += Indent + Indent + "return None\n\n";
+  }
+
+  // Get the value of a string.
+  void GetStringField(const StructDef &struct_def, const FieldDef &field,
+                      std::string *code_ptr) {
+    auto &code = *code_ptr;
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    code += "(self):";
+    code += OffsetPrefix(field);
+    code += Indent + Indent + Indent + "return " + GenGetter(field.value.type);
+    code += "o + self._tab.Pos)\n";
+    code += Indent + Indent + "return None\n\n";
+  }
+
+  // Get the value of a union from an object.
+  void GetUnionField(const StructDef &struct_def, const FieldDef &field,
+                     std::string *code_ptr) {
+    auto &code = *code_ptr;
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field)) + "(self):";
+    code += OffsetPrefix(field);
+
+    // TODO(rw): this works and is not the good way to it:
+    bool is_native_table = TypeName(field) == "*flatbuffers.Table";
+    if (is_native_table) {
+      code +=
+          Indent + Indent + Indent + "from flatbuffers.table import Table\n";
+    } else if (parser_.opts.include_dependence_headers) {
+      code += Indent + Indent + Indent;
+      code += "from " + GenPackageReference(field.value.type) + " import " +
+              TypeName(field) + "\n";
+    }
+    code += Indent + Indent + Indent + "obj = Table(bytearray(), 0)\n";
+    code += Indent + Indent + Indent + GenGetter(field.value.type);
+    code += "obj, o)\n" + Indent + Indent + Indent + "return obj\n";
+    code += Indent + Indent + "return None\n\n";
+  }
+
+  // Generate the package reference when importing a struct or enum from its
+  // module.
+  std::string GenPackageReference(const Type &type) {
+    Namespace *namespaces;
+    if (type.struct_def) {
+      namespaces = type.struct_def->defined_namespace;
+    } else if (type.enum_def) {
+      namespaces = type.enum_def->defined_namespace;
+    } else {
+      return "." + GenTypeGet(type);
+    }
+
+    return namespaces->GetFullyQualifiedName(GenTypeGet(type));
+  }
+
+  // Get the value of a vector's struct member.
+  void GetMemberOfVectorOfStruct(const StructDef &struct_def,
+                                 const FieldDef &field, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto vectortype = field.value.type.VectorType();
+
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    code += "(self, j):" + OffsetPrefix(field);
+    code += Indent + Indent + Indent + "x = self._tab.Vector(o)\n";
+    code += Indent + Indent + Indent;
+    code += "x += flatbuffers.number_types.UOffsetTFlags.py_type(j) * ";
+    code += NumToString(InlineSize(vectortype)) + "\n";
+    if (!(vectortype.struct_def->fixed)) {
+      code += Indent + Indent + Indent + "x = self._tab.Indirect(x)\n";
+    }
+    if (parser_.opts.include_dependence_headers) {
+      code += Indent + Indent + Indent;
+      code += "from " + GenPackageReference(field.value.type) + " import " +
+              TypeName(field) + "\n";
+    }
+    code += Indent + Indent + Indent + "obj = " + TypeName(field) + "()\n";
+    code += Indent + Indent + Indent + "obj.Init(self._tab.Bytes, x)\n";
+    code += Indent + Indent + Indent + "return obj\n";
+    code += Indent + Indent + "return None\n\n";
+  }
+
+  // Get the value of a vector's non-struct member. Uses a named return
+  // argument to conveniently set the zero value for the result.
+  void GetMemberOfVectorOfNonStruct(const StructDef &struct_def,
+                                    const FieldDef &field,
+                                    std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto vectortype = field.value.type.VectorType();
+
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field));
+    code += "(self, j):";
+    code += OffsetPrefix(field);
+    code += Indent + Indent + Indent + "a = self._tab.Vector(o)\n";
+    code += Indent + Indent + Indent;
+    code += "return " + GenGetter(field.value.type);
+    code += "a + flatbuffers.number_types.UOffsetTFlags.py_type(j * ";
+    code += NumToString(InlineSize(vectortype)) + "))\n";
+    if (IsString(vectortype)) {
+      code += Indent + Indent + "return \"\"\n";
+    } else {
+      code += Indent + Indent + "return 0\n";
+    }
+    code += "\n";
+  }
+
+  // Returns a non-struct vector as a numpy array. Much faster
+  // than iterating over the vector element by element.
+  void GetVectorOfNonStructAsNumpy(const StructDef &struct_def,
+                                   const FieldDef &field,
+                                   std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto vectortype = field.value.type.VectorType();
+
+    // Currently, we only support accessing as numpy array if
+    // the vector type is a scalar.
+    if (!(IsScalar(vectortype.base_type))) { return; }
+
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field)) + "AsNumpy(self):";
+    code += OffsetPrefix(field);
+
+    code += Indent + Indent + Indent;
+    code += "return ";
+    code += "self._tab.GetVectorAsNumpy(flatbuffers.number_types.";
+    code += MakeCamel(GenTypeGet(field.value.type));
+    code += "Flags, o)\n";
+
+    if (IsString(vectortype)) {
+      code += Indent + Indent + "return \"\"\n";
+    } else {
+      code += Indent + Indent + "return 0\n";
+    }
+    code += "\n";
+  }
+
+  // Returns a nested flatbuffer as itself.
+  void GetVectorAsNestedFlatbuffer(const StructDef &struct_def,
+                                   const FieldDef &field,
+                                   std::string *code_ptr) {
+    auto nested = field.attributes.Lookup("nested_flatbuffer");
+    if (!nested) { return; }  // There is no nested flatbuffer.
+
+    std::string unqualified_name = nested->constant;
+    std::string qualified_name = nested->constant;
+    auto nested_root = parser_.LookupStruct(nested->constant);
+    if (nested_root == nullptr) {
+      qualified_name =
+          parser_.current_namespace_->GetFullyQualifiedName(nested->constant);
+      nested_root = parser_.LookupStruct(qualified_name);
+    }
+    FLATBUFFERS_ASSERT(nested_root);  // Guaranteed to exist by parser.
+    (void)nested_root;
+
+    auto &code = *code_ptr;
+    GenReceiver(struct_def, code_ptr);
+    code += MakeCamel(NormalizedName(field)) + "NestedRoot(self):";
+
+    code += OffsetPrefix(field);
+
+    code += Indent + Indent + Indent;
+    code += "from " + qualified_name + " import " + unqualified_name + "\n";
+    code += Indent + Indent + Indent + "return " + unqualified_name;
+    code += ".GetRootAs";
+    code += "(self._tab.Bytes, self._tab.Vector(o))\n";
+    code += Indent + Indent + "return 0\n";
+    code += "\n";
+  }
+
+  // Begin the creator function signature.
+  void BeginBuilderArgs(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+
+    code += "\n";
+    code += "def Create" + NormalizedName(struct_def);
+    code += "(builder";
+  }
+
+  // Recursively generate arguments for a constructor, to deal with nested
+  // structs.
+  void StructBuilderArgs(const StructDef &struct_def,
+                         const std::string nameprefix,
+                         const std::string namesuffix, bool has_field_name,
+                         const std::string fieldname_suffix,
+                         std::string *code_ptr) {
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      const auto &field_type = field.value.type;
+      const auto &type =
+          IsArray(field_type) ? field_type.VectorType() : field_type;
+      if (IsStruct(type)) {
+        // Generate arguments for a struct inside a struct. To ensure names
+        // don't clash, and to make it obvious these arguments are constructing
+        // a nested struct, prefix the name with the field name.
+        auto subprefix = nameprefix;
+        if (has_field_name) {
+          subprefix += NormalizedName(field) + fieldname_suffix;
+        }
+        StructBuilderArgs(*field.value.type.struct_def, subprefix, namesuffix,
+                          has_field_name, fieldname_suffix, code_ptr);
+      } else {
+        auto &code = *code_ptr;
+        code += std::string(", ") + nameprefix;
+        if (has_field_name) { code += MakeCamel(NormalizedName(field), false); }
+        code += namesuffix;
+      }
+    }
+  }
+
+  // End the creator function signature.
+  void EndBuilderArgs(std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "):\n";
+  }
+
+  // Recursively generate struct construction statements and instert manual
+  // padding.
+  void StructBuilderBody(const StructDef &struct_def, const char *nameprefix,
+                         std::string *code_ptr, size_t index = 0,
+                         bool in_array = false) {
+    auto &code = *code_ptr;
+    std::string indent(index * 4, ' ');
+    code +=
+        indent + "    builder.Prep(" + NumToString(struct_def.minalign) + ", ";
+    code += NumToString(struct_def.bytesize) + ")\n";
+    for (auto it = struct_def.fields.vec.rbegin();
+         it != struct_def.fields.vec.rend(); ++it) {
+      auto &field = **it;
+      const auto &field_type = field.value.type;
+      const auto &type =
+          IsArray(field_type) ? field_type.VectorType() : field_type;
+      if (field.padding)
+        code +=
+            indent + "    builder.Pad(" + NumToString(field.padding) + ")\n";
+      if (IsStruct(field_type)) {
+        StructBuilderBody(*field_type.struct_def,
+                          (nameprefix + (NormalizedName(field) + "_")).c_str(),
+                          code_ptr, index, in_array);
+      } else {
+        const auto index_var = "_idx" + NumToString(index);
+        if (IsArray(field_type)) {
+          code += indent + "    for " + index_var + " in range(";
+          code += NumToString(field_type.fixed_length);
+          code += " , 0, -1):\n";
+          in_array = true;
+        }
+        if (IsStruct(type)) {
+          StructBuilderBody(
+              *field_type.struct_def,
+              (nameprefix + (NormalizedName(field) + "_")).c_str(), code_ptr,
+              index + 1, in_array);
+        } else {
+          code += IsArray(field_type) ? "    " : "";
+          code += indent + "    builder.Prepend" + GenMethod(field) + "(";
+          code += nameprefix + MakeCamel(NormalizedName(field), false);
+          size_t array_cnt = index + (IsArray(field_type) ? 1 : 0);
+          for (size_t i = 0; in_array && i < array_cnt; i++) {
+            code += "[_idx" + NumToString(i) + "-1]";
+          }
+          code += ")\n";
+        }
+      }
+    }
+  }
+
+  void EndBuilderBody(std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "    return builder.Offset()\n";
+  }
+
+  // Get the value of a table's starting offset.
+  void GetStartOfTable(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "def Start(builder): ";
+    code += "builder.StartObject(";
+    code += NumToString(struct_def.fields.vec.size());
+    code += ")\n";
+
+    // Add alias with the old name.
+    code += "def " + NormalizedName(struct_def) + "Start(builder):\n";
+    code += Indent + "\"\"\"This method is deprecated. Please switch to Start.\"\"\"\n";
+    code += Indent + "return Start(builder)\n";
+  }
+
+  // Set the value of a table's field.
+  void BuildFieldOfTable(const StructDef &struct_def, const FieldDef &field,
+                         const size_t offset, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "def Add" + MakeCamel(NormalizedName(field));
+    code += "(builder, ";
+    code += MakeCamel(NormalizedName(field), false);
+    code += "): ";
+    code += "builder.Prepend";
+    code += GenMethod(field) + "Slot(";
+    code += NumToString(offset) + ", ";
+    if (!IsScalar(field.value.type.base_type) && (!struct_def.fixed)) {
+      code += "flatbuffers.number_types.UOffsetTFlags.py_type";
+      code += "(";
+      code += MakeCamel(NormalizedName(field), false) + ")";
+    } else {
+      code += MakeCamel(NormalizedName(field), false);
+    }
+    code += ", ";
+    code += IsFloat(field.value.type.base_type)
+                ? float_const_gen_.GenFloatConstant(field)
+                : field.value.constant;
+    code += ")\n";
+
+    // Add alias with the old name.
+    code += "def " + NormalizedName(struct_def) + "Add" + MakeCamel(NormalizedName(field));
+    code += "(builder, ";
+    code += MakeCamel(NormalizedName(field), false);
+    code += "):\n";
+    code += Indent + "\"\"\"This method is deprecated. Please switch to Add";
+    code += MakeCamel(NormalizedName(field)) + ".\"\"\"\n";
+    code += Indent + "return Add" + MakeCamel(NormalizedName(field));
+    code += "(builder, ";
+    code += MakeCamel(NormalizedName(field), false);
+    code += ")\n";
+
+    // Add alias with the old name.
+  }
+
+  // Set the value of one of the members of a table's vector.
+  void BuildVectorOfTable(const StructDef &struct_def, const FieldDef &field,
+                          std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "def Start";
+    code += MakeCamel(NormalizedName(field));
+    code += "Vector(builder, numElems): return builder.StartVector(";
+    auto vector_type = field.value.type.VectorType();
+    auto alignment = InlineAlignment(vector_type);
+    auto elem_size = InlineSize(vector_type);
+    code += NumToString(elem_size);
+    code += ", numElems, " + NumToString(alignment);
+    code += ")\n";
+
+    // Add alias with the old name.
+    code += "def " + NormalizedName(struct_def) + "Start";
+    code += MakeCamel(NormalizedName(field));
+    code += "Vector(builder, numElems):\n";
+    code += Indent + "\"\"\"This method is deprecated. Please switch to Start.\"\"\"\n";
+    code += Indent + "return Start";
+    code += MakeCamel(NormalizedName(field));
+    code += "Vector(builder, numElems)\n";
+  }
+
+  // Set the value of one of the members of a table's vector and fills in the
+  // elements from a bytearray. This is for simplifying the use of nested
+  // flatbuffers.
+  void BuildVectorOfTableFromBytes(const FieldDef &field, std::string *code_ptr) {
+    auto nested = field.attributes.Lookup("nested_flatbuffer");
+    if (!nested) { return; }  // There is no nested flatbuffer.
+
+    std::string unqualified_name = nested->constant;
+    std::string qualified_name = nested->constant;
+    auto nested_root = parser_.LookupStruct(nested->constant);
+    if (nested_root == nullptr) {
+      qualified_name =
+          parser_.current_namespace_->GetFullyQualifiedName(nested->constant);
+      nested_root = parser_.LookupStruct(qualified_name);
+    }
+    FLATBUFFERS_ASSERT(nested_root);  // Guaranteed to exist by parser.
+    (void)nested_root;
+
+    auto &code = *code_ptr;
+    code += "def MakeVectorFromBytes(builder, bytes):\n";
+    code += Indent + "builder.StartVector(";
+    auto vector_type = field.value.type.VectorType();
+    auto alignment = InlineAlignment(vector_type);
+    auto elem_size = InlineSize(vector_type);
+    code += NumToString(elem_size);
+    code += ", len(bytes), " + NumToString(alignment);
+    code += ")\n";
+    code += Indent + "builder.head = builder.head - len(bytes)\n";
+    code += Indent + "builder.Bytes[builder.head : builder.head + len(bytes)]";
+    code += " = bytes\n";
+    code += Indent + "return builder.EndVector()\n";
+
+    // Add alias with the old name.
+    code += "def Make" + MakeCamel(NormalizedName(field));
+    code += "VectorFromBytes(builder, bytes):\n";
+    code += Indent + "builder.StartVector(";
+    code += NumToString(elem_size);
+    code += ", len(bytes), " + NumToString(alignment);
+    code += ")\n";
+    code += Indent + "builder.head = builder.head - len(bytes)\n";
+    code += Indent + "builder.Bytes[builder.head : builder.head + len(bytes)]";
+    code += " = bytes\n";
+    code += Indent + "return builder.EndVector()\n";
+  }
+
+  // Get the offset of the end of a table.
+  void GetEndOffsetOnTable(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "def End(builder): return builder.EndObject()\n";
+
+    // Add alias with the old name.
+    code += "def " + NormalizedName(struct_def) + "End(builder):\n";
+    code += Indent + "\"\"\"This method is deprecated. Please switch to End.\"\"\"\n";
+    code += Indent + "return End(builder)";
+  }
+
+  // Generate the receiver for function signatures.
+  void GenReceiver(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += Indent + "# " + NormalizedName(struct_def) + "\n";
+    code += Indent + "def ";
+  }
+
+  // Generate a struct field, conditioned on its child type(s).
+  void GenStructAccessor(const StructDef &struct_def, const FieldDef &field,
+                         std::string *code_ptr) {
+    GenComment(field.doc_comment, code_ptr, &def_comment, Indent.c_str());
+    if (IsScalar(field.value.type.base_type)) {
+      if (struct_def.fixed) {
+        GetScalarFieldOfStruct(struct_def, field, code_ptr);
+      } else {
+        GetScalarFieldOfTable(struct_def, field, code_ptr);
+      }
+    } else if (IsArray(field.value.type)) {
+      GetArrayOfStruct(struct_def, field, code_ptr);
+    } else {
+      switch (field.value.type.base_type) {
+        case BASE_TYPE_STRUCT:
+          if (struct_def.fixed) {
+            GetStructFieldOfStruct(struct_def, field, code_ptr);
+          } else {
+            GetStructFieldOfTable(struct_def, field, code_ptr);
+          }
+          break;
+        case BASE_TYPE_STRING:
+          GetStringField(struct_def, field, code_ptr);
+          break;
+        case BASE_TYPE_VECTOR: {
+          auto vectortype = field.value.type.VectorType();
+          if (vectortype.base_type == BASE_TYPE_STRUCT) {
+            GetMemberOfVectorOfStruct(struct_def, field, code_ptr);
+          } else {
+            GetMemberOfVectorOfNonStruct(struct_def, field, code_ptr);
+            GetVectorOfNonStructAsNumpy(struct_def, field, code_ptr);
+            GetVectorAsNestedFlatbuffer(struct_def, field, code_ptr);
+          }
+          break;
+        }
+        case BASE_TYPE_UNION: GetUnionField(struct_def, field, code_ptr); break;
+        default: FLATBUFFERS_ASSERT(0);
+      }
+    }
+    if (IsVector(field.value.type) || IsArray(field.value.type)) {
+      GetVectorLen(struct_def, field, code_ptr);
+      GetVectorIsNone(struct_def, field, code_ptr);
+    }
+  }
+
+  // Generate struct sizeof.
+  void GenStructSizeOf(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += Indent + "@classmethod\n";
+    code += Indent + "def SizeOf(cls):\n";
+    code +=
+        Indent + Indent + "return " + NumToString(struct_def.bytesize) + "\n";
+    code += "\n";
+  }
+
+  // Generate table constructors, conditioned on its members' types.
+  void GenTableBuilders(const StructDef &struct_def, std::string *code_ptr) {
+    GetStartOfTable(struct_def, code_ptr);
+
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      auto offset = it - struct_def.fields.vec.begin();
+      BuildFieldOfTable(struct_def, field, offset, code_ptr);
+      if (IsVector(field.value.type)) {
+        BuildVectorOfTable(struct_def, field, code_ptr);
+        BuildVectorOfTableFromBytes(field, code_ptr);
+      }
+    }
+
+    GetEndOffsetOnTable(struct_def, code_ptr);
+  }
+
+  // Generate function to check for proper file identifier
+  void GenHasFileIdentifier(const StructDef &struct_def,
+                            std::string *code_ptr) {
+    auto &code = *code_ptr;
+    std::string escapedID;
+    // In the event any of file_identifier characters are special(NULL, \, etc),
+    // problems occur. To prevent this, convert all chars to their hex-escaped
+    // equivalent.
+    for (auto it = parser_.file_identifier_.begin();
+         it != parser_.file_identifier_.end(); ++it) {
+      escapedID += "\\x" + IntToStringHex(*it, 2);
+    }
+
+    code += Indent + "@classmethod\n";
+    code += Indent + "def " + NormalizedName(struct_def);
+    code += "BufferHasIdentifier(cls, buf, offset, size_prefixed=False):";
+    code += "\n";
+    code += Indent + Indent;
+    code += "return flatbuffers.util.BufferHasIdentifier(buf, offset, b\"";
+    code += escapedID;
+    code += "\", size_prefixed=size_prefixed)\n";
+    code += "\n";
+  }
+
+  // Generates struct or table methods.
+  void GenStruct(const StructDef &struct_def, std::string *code_ptr) {
+    if (struct_def.generated) return;
+
+    GenComment(struct_def.doc_comment, code_ptr, &def_comment);
+    BeginClass(struct_def, code_ptr);
+    if (!struct_def.fixed) {
+      // Generate a special accessor for the table that has been declared as
+      // the root type.
+      NewRootTypeFromBuffer(struct_def, code_ptr);
+      if (parser_.file_identifier_.length()) {
+        // Generate a special function to test file_identifier
+        GenHasFileIdentifier(struct_def, code_ptr);
+      }
+    } else {
+      // Generates the SizeOf method for all structs.
+      GenStructSizeOf(struct_def, code_ptr);
+    }
+    // Generates the Init method that sets the field in a pre-existing
+    // accessor object. This is to allow object reuse.
+    InitializeExisting(struct_def, code_ptr);
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      GenStructAccessor(struct_def, field, code_ptr);
+    }
+
+    if (struct_def.fixed) {
+      // creates a struct constructor function
+      GenStructBuilder(struct_def, code_ptr);
+    } else {
+      // Creates a set of functions that allow table construction.
+      GenTableBuilders(struct_def, code_ptr);
+    }
+  }
+
+  void GenReceiverForObjectAPI(const StructDef &struct_def,
+                               std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += GenIndents(1) + "# " + NormalizedName(struct_def) + "T";
+    code += GenIndents(1) + "def ";
+  }
+
+  void BeginClassForObjectAPI(const StructDef &struct_def,
+                              std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code += "\n";
+    code += "class " + NormalizedName(struct_def) + "T(object):";
+    code += "\n";
+  }
+
+  // Gets the accoresponding python builtin type of a BaseType for scalars and
+  // string.
+  std::string GetBasePythonTypeForScalarAndString(const BaseType &base_type) {
+    if (IsBool(base_type)) {
+      return "bool";
+    } else if (IsFloat(base_type)) {
+      return "float";
+    } else if (IsInteger(base_type)) {
+      return "int";
+    } else if (base_type == BASE_TYPE_STRING) {
+      return "str";
+    } else {
+      FLATBUFFERS_ASSERT(false && "base_type is not a scalar or string type.");
+      return "";
+    }
+  }
+
+  std::string GetDefaultValue(const FieldDef &field) {
+    BaseType base_type = field.value.type.base_type;
+    if (IsBool(base_type)) {
+      return field.value.constant == "0" ? "False" : "True";
+    } else if (IsFloat(base_type)) {
+      return float_const_gen_.GenFloatConstant(field);
+    } else if (IsInteger(base_type)) {
+      return field.value.constant;
+    } else {
+      // For string, struct, and table.
+      return "None";
+    }
+  }
+
+  void GenUnionInit(const FieldDef &field, std::string *field_types_ptr,
+                    std::set<std::string> *import_list,
+                    std::set<std::string> *import_typing_list) {
+    // Gets all possible types in the union.
+    import_typing_list->insert("Union");
+    auto &field_types = *field_types_ptr;
+    field_types = "Union[";
+
+    std::string separator_string = ", ";
+    auto enum_def = field.value.type.enum_def;
+    for (auto it = enum_def->Vals().begin(); it != enum_def->Vals().end();
+         ++it) {
+      auto &ev = **it;
+      // Union only supports string and table.
+      std::string field_type;
+      switch (ev.union_type.base_type) {
+        case BASE_TYPE_STRUCT:
+          field_type = GenTypeGet(ev.union_type) + "T";
+          if (parser_.opts.include_dependence_headers) {
+            auto package_reference = GenPackageReference(ev.union_type);
+            field_type = package_reference + "." + field_type;
+            import_list->insert("import " + package_reference);
+          }
+          break;
+        case BASE_TYPE_STRING: field_type += "str"; break;
+        case BASE_TYPE_NONE: field_type += "None"; break;
+        default: break;
+      }
+      field_types += field_type + separator_string;
+    }
+
+    // Removes the last separator_string.
+    field_types.erase(field_types.length() - separator_string.size());
+    field_types += "]";
+
+    // Gets the import lists for the union.
+    if (parser_.opts.include_dependence_headers) {
+      // The package reference is generated based on enum_def, instead
+      // of struct_def in field.type. That's why GenPackageReference() is
+      // not used.
+      Namespace *namespaces = field.value.type.enum_def->defined_namespace;
+      auto package_reference = namespaces->GetFullyQualifiedName(
+          MakeUpperCamel(*(field.value.type.enum_def)));
+      auto union_name = MakeUpperCamel(*(field.value.type.enum_def));
+      import_list->insert("import " + package_reference);
+    }
+  }
+
+  void GenStructInit(const FieldDef &field, std::string *field_type_ptr,
+                     std::set<std::string> *import_list,
+                     std::set<std::string> *import_typing_list) {
+    import_typing_list->insert("Optional");
+    auto &field_type = *field_type_ptr;
+    if (parser_.opts.include_dependence_headers) {
+      auto package_reference = GenPackageReference(field.value.type);
+      field_type = package_reference + "." + TypeName(field) + "T]";
+      import_list->insert("import " + package_reference);
+    } else {
+      field_type = TypeName(field) + "T]";
+    }
+    field_type = "Optional[" + field_type;
+  }
+
+  void GenVectorInit(const FieldDef &field, std::string *field_type_ptr,
+                     std::set<std::string> *import_list,
+                     std::set<std::string> *import_typing_list) {
+    import_typing_list->insert("List");
+    auto &field_type = *field_type_ptr;
+    auto base_type = field.value.type.VectorType().base_type;
+    if (base_type == BASE_TYPE_STRUCT) {
+      field_type = GenTypeGet(field.value.type.VectorType()) + "T]";
+      if (parser_.opts.include_dependence_headers) {
+        auto package_reference =
+            GenPackageReference(field.value.type.VectorType());
+        field_type = package_reference + "." +
+                     GenTypeGet(field.value.type.VectorType()) + "T]";
+        import_list->insert("import " + package_reference);
+      }
+      field_type = "List[" + field_type;
+    } else {
+      field_type =
+          "List[" + GetBasePythonTypeForScalarAndString(base_type) + "]";
+    }
+  }
+
+  void GenInitialize(const StructDef &struct_def, std::string *code_ptr,
+                     std::set<std::string> *import_list) {
+    std::string code;
+    std::set<std::string> import_typing_list;
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      // Determines field type, default value, and typing imports.
+      auto base_type = field.value.type.base_type;
+      std::string field_type;
+      switch (base_type) {
+        case BASE_TYPE_UNION: {
+          GenUnionInit(field, &field_type, import_list, &import_typing_list);
+          break;
+        }
+        case BASE_TYPE_STRUCT: {
+          GenStructInit(field, &field_type, import_list, &import_typing_list);
+          break;
+        }
+        case BASE_TYPE_VECTOR:
+        case BASE_TYPE_ARRAY: {
+          GenVectorInit(field, &field_type, import_list, &import_typing_list);
+          break;
+        }
+        default:
+          // Scalar or sting fields.
+          field_type = GetBasePythonTypeForScalarAndString(base_type);
+          break;
+      }
+
+      auto default_value = GetDefaultValue(field);
+      // Wrties the init statement.
+      auto field_instance_name = MakeLowerCamel(field);
+      code += GenIndents(2) + "self." + field_instance_name + " = " +
+              default_value + "  # type: " + field_type;
+    }
+
+    // Writes __init__ method.
+    auto &code_base = *code_ptr;
+    GenReceiverForObjectAPI(struct_def, code_ptr);
+    code_base += "__init__(self):";
+    if (code.empty()) {
+      code_base += GenIndents(2) + "pass";
+    } else {
+      code_base += code;
+    }
+    code_base += "\n";
+
+    // Merges the typing imports into import_list.
+    if (!import_typing_list.empty()) {
+      // Adds the try statement.
+      std::string typing_imports = "try:";
+      typing_imports += GenIndents(1) + "from typing import ";
+      std::string separator_string = ", ";
+      for (auto it = import_typing_list.begin(); it != import_typing_list.end();
+           ++it) {
+        const std::string &im = *it;
+        typing_imports += im + separator_string;
+      }
+      // Removes the last separator_string.
+      typing_imports.erase(typing_imports.length() - separator_string.size());
+
+      // Adds the except statement.
+      typing_imports += "\n";
+      typing_imports += "except:";
+      typing_imports += GenIndents(1) + "pass";
+      import_list->insert(typing_imports);
+    }
+
+    // Removes the import of the struct itself, if applied.
+    auto package_reference =
+        struct_def.defined_namespace->GetFullyQualifiedName(
+            MakeUpperCamel(struct_def));
+    auto struct_import = "import " + package_reference;
+    import_list->erase(struct_import);
+  }
+
+  void InitializeFromBuf(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto instance_name = MakeLowerCamel(struct_def);
+    auto struct_name = NormalizedName(struct_def);
+
+    code += GenIndents(1) + "@classmethod";
+    code += GenIndents(1) + "def InitFromBuf(cls, buf, pos):";
+    code += GenIndents(2) + instance_name + " = " + struct_name + "()";
+    code += GenIndents(2) + instance_name + ".Init(buf, pos)";
+    code += GenIndents(2) + "return cls.InitFromObj(" + instance_name + ")";
+    code += "\n";
+  }
+
+  void InitializeFromObjForObject(const StructDef &struct_def,
+                                  std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto instance_name = MakeLowerCamel(struct_def);
+    auto struct_name = NormalizedName(struct_def);
+
+    code += GenIndents(1) + "@classmethod";
+    code += GenIndents(1) + "def InitFromObj(cls, " + instance_name + "):";
+    code += GenIndents(2) + "x = " + struct_name + "T()";
+    code += GenIndents(2) + "x._UnPack(" + instance_name + ")";
+    code += GenIndents(2) + "return x";
+    code += "\n";
+  }
+
+  void GenUnPackForStruct(const StructDef &struct_def, const FieldDef &field,
+                          std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto field_type = TypeName(field);
+
+    if (parser_.opts.include_dependence_headers) {
+      auto package_reference = GenPackageReference(field.value.type);
+      field_type = package_reference + "." + TypeName(field);
+    }
+
+    code += GenIndents(2) + "if " + struct_instance_name + "." +
+            field_accessor_name + "(";
+    // if field is a struct, we need to create an instance for it first.
+    if (struct_def.fixed && field.value.type.base_type == BASE_TYPE_STRUCT) {
+      code += field_type + "()";
+    }
+    code += ") is not None:";
+    code += GenIndents(3) + "self." + field_instance_name + " = " + field_type +
+            "T.InitFromObj(" + struct_instance_name + "." +
+            field_accessor_name + "(";
+    // A struct's accessor requires a struct buf instance.
+    if (struct_def.fixed && field.value.type.base_type == BASE_TYPE_STRUCT) {
+      code += field_type + "()";
+    }
+    code += "))";
+  }
+
+  void GenUnPackForUnion(const StructDef &struct_def, const FieldDef &field,
+                         std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+    auto union_name = MakeUpperCamel(*(field.value.type.enum_def));
+
+    if (parser_.opts.include_dependence_headers) {
+      Namespace *namespaces = field.value.type.enum_def->defined_namespace;
+      auto package_reference = namespaces->GetFullyQualifiedName(
+          MakeUpperCamel(*(field.value.type.enum_def)));
+      union_name = package_reference + "." + union_name;
+    }
+    code += GenIndents(2) + "self." + field_instance_name + " = " + union_name +
+            "Creator(" + "self." + field_instance_name + "Type, " +
+            struct_instance_name + "." + field_accessor_name + "())";
+  }
+
+  void GenUnPackForStructVector(const StructDef &struct_def,
+                                const FieldDef &field, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+
+    code += GenIndents(2) + "if not " + struct_instance_name + "." +
+            field_accessor_name + "IsNone():";
+    code += GenIndents(3) + "self." + field_instance_name + " = []";
+    code += GenIndents(3) + "for i in range(" + struct_instance_name + "." +
+            field_accessor_name + "Length()):";
+
+    auto field_type_name = TypeName(field);
+    auto one_instance = field_type_name + "_";
+    one_instance[0] = CharToLower(one_instance[0]);
+
+    if (parser_.opts.include_dependence_headers) {
+      auto package_reference = GenPackageReference(field.value.type);
+      field_type_name = package_reference + "." + TypeName(field);
+    }
+
+    code += GenIndents(4) + "if " + struct_instance_name + "." +
+            field_accessor_name + "(i) is None:";
+    code += GenIndents(5) + "self." + field_instance_name + ".append(None)";
+    code += GenIndents(4) + "else:";
+    code += GenIndents(5) + one_instance + " = " + field_type_name +
+            "T.InitFromObj(" + struct_instance_name + "." +
+            field_accessor_name + "(i))";
+    code += GenIndents(5) + "self." + field_instance_name + ".append(" +
+            one_instance + ")";
+  }
+
+  void GenUnpackforScalarVectorHelper(const StructDef &struct_def,
+                                      const FieldDef &field,
+                                      std::string *code_ptr, int indents) {
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+
+    code += GenIndents(indents) + "self." + field_instance_name + " = []";
+    code += GenIndents(indents) + "for i in range(" + struct_instance_name +
+            "." + field_accessor_name + "Length()):";
+    code += GenIndents(indents + 1) + "self." + field_instance_name +
+            ".append(" + struct_instance_name + "." + field_accessor_name +
+            "(i))";
+  }
+
+  void GenUnPackForScalarVector(const StructDef &struct_def,
+                                const FieldDef &field, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+
+    code += GenIndents(2) + "if not " + struct_instance_name + "." +
+            field_accessor_name + "IsNone():";
+
+    // String does not have the AsNumpy method.
+    if (!(IsScalar(field.value.type.VectorType().base_type))) {
+      GenUnpackforScalarVectorHelper(struct_def, field, code_ptr, 3);
+      return;
+    }
+
+    code += GenIndents(3) + "if np is None:";
+    GenUnpackforScalarVectorHelper(struct_def, field, code_ptr, 4);
+
+    // If numpy exists, use the AsNumpy method to optimize the unpack speed.
+    code += GenIndents(3) + "else:";
+    code += GenIndents(4) + "self." + field_instance_name + " = " +
+            struct_instance_name + "." + field_accessor_name + "AsNumpy()";
+  }
+
+  void GenUnPackForScalar(const StructDef &struct_def, const FieldDef &field,
+                          std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+
+    code += GenIndents(2) + "self." + field_instance_name + " = " +
+            struct_instance_name + "." + field_accessor_name + "()";
+  }
+
+  // Generates the UnPack method for the object class.
+  void GenUnPack(const StructDef &struct_def, std::string *code_ptr) {
+    std::string code;
+    // Items that needs to be imported. No duplicate modules will be imported.
+    std::set<std::string> import_list;
+
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      auto field_type = TypeName(field);
+      switch (field.value.type.base_type) {
+        case BASE_TYPE_STRUCT: {
+          GenUnPackForStruct(struct_def, field, &code);
+          break;
+        }
+        case BASE_TYPE_UNION: {
+          GenUnPackForUnion(struct_def, field, &code);
+          break;
+        }
+        case BASE_TYPE_VECTOR: {
+          auto vectortype = field.value.type.VectorType();
+          if (vectortype.base_type == BASE_TYPE_STRUCT) {
+            GenUnPackForStructVector(struct_def, field, &code);
+          } else {
+            GenUnPackForScalarVector(struct_def, field, &code);
+          }
+          break;
+        }
+        case BASE_TYPE_ARRAY: {
+          GenUnPackForScalarVector(struct_def, field, &code);
+          break;
+        }
+        default: GenUnPackForScalar(struct_def, field, &code);
+      }
+    }
+
+    // Writes import statements and code into the generated file.
+    auto &code_base = *code_ptr;
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+    auto struct_name = MakeUpperCamel(struct_def);
+
+    GenReceiverForObjectAPI(struct_def, code_ptr);
+    code_base += "_UnPack(self, " + struct_instance_name + "):";
+    code_base += GenIndents(2) + "if " + struct_instance_name + " is None:";
+    code_base += GenIndents(3) + "return";
+
+    // Write the import statements.
+    for (std::set<std::string>::iterator it = import_list.begin();
+         it != import_list.end(); ++it) {
+      code_base += GenIndents(2) + *it;
+    }
+
+    // Write the code.
+    code_base += code;
+    code_base += "\n";
+  }
+
+  void GenPackForStruct(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto struct_name = MakeUpperCamel(struct_def);
+
+    GenReceiverForObjectAPI(struct_def, code_ptr);
+    code += "Pack(self, builder):";
+    code += GenIndents(2) + "return Create" + struct_name + "(builder";
+
+    StructBuilderArgs(struct_def,
+                      /* nameprefix = */ "self.",
+                      /* namesuffix = */ "",
+                      /* has_field_name = */ true,
+                      /* fieldname_suffix = */ ".", code_ptr);
+    code += ")\n";
+  }
+
+  void GenPackForStructVectorField(const StructDef &struct_def,
+                                   const FieldDef &field,
+                                   std::string *code_prefix_ptr,
+                                   std::string *code_ptr) {
+    auto &code_prefix = *code_prefix_ptr;
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto struct_name = NormalizedName(struct_def);
+    auto field_accessor_name = MakeUpperCamel(field);
+
+    // Creates the field.
+    code_prefix +=
+        GenIndents(2) + "if self." + field_instance_name + " is not None:";
+    if (field.value.type.struct_def->fixed) {
+      code_prefix += GenIndents(3) + "Start" +
+                     field_accessor_name + "Vector(builder, len(self." +
+                     field_instance_name + "))";
+      code_prefix += GenIndents(3) + "for i in reversed(range(len(self." +
+                     field_instance_name + "))):";
+      code_prefix +=
+          GenIndents(4) + "self." + field_instance_name + "[i].Pack(builder)";
+      code_prefix +=
+          GenIndents(3) + field_instance_name + " = builder.EndVector()";
+    } else {
+      // If the vector is a struct vector, we need to first build accessor for
+      // each struct element.
+      code_prefix += GenIndents(3) + field_instance_name + "list = []";
+      code_prefix += GenIndents(3);
+      code_prefix += "for i in range(len(self." + field_instance_name + ")):";
+      code_prefix += GenIndents(4) + field_instance_name + "list.append(self." +
+                     field_instance_name + "[i].Pack(builder))";
+
+      code_prefix += GenIndents(3) + "Start" +
+                     field_accessor_name + "Vector(builder, len(self." +
+                     field_instance_name + "))";
+      code_prefix += GenIndents(3) + "for i in reversed(range(len(self." +
+                     field_instance_name + "))):";
+      code_prefix += GenIndents(4) + "builder.PrependUOffsetTRelative" + "(" +
+                     field_instance_name + "list[i])";
+      code_prefix +=
+          GenIndents(3) + field_instance_name + " = builder.EndVector()";
+    }
+
+    // Adds the field into the struct.
+    code += GenIndents(2) + "if self." + field_instance_name + " is not None:";
+    code += GenIndents(3) + "Add" + field_accessor_name +
+            "(builder, " + field_instance_name + ")";
+  }
+
+  void GenPackForScalarVectorFieldHelper(const StructDef &struct_def,
+                                         const FieldDef &field,
+                                         std::string *code_ptr, int indents) {
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_name = NormalizedName(struct_def);
+    auto vectortype = field.value.type.VectorType();
+
+    code += GenIndents(indents) + "Start" + field_accessor_name +
+            "Vector(builder, len(self." + field_instance_name + "))";
+    code += GenIndents(indents) + "for i in reversed(range(len(self." +
+            field_instance_name + "))):";
+    code += GenIndents(indents + 1) + "builder.Prepend";
+
+    std::string type_name;
+    switch (vectortype.base_type) {
+      case BASE_TYPE_BOOL: type_name = "Bool"; break;
+      case BASE_TYPE_CHAR: type_name = "Byte"; break;
+      case BASE_TYPE_UCHAR: type_name = "Uint8"; break;
+      case BASE_TYPE_SHORT: type_name = "Int16"; break;
+      case BASE_TYPE_USHORT: type_name = "Uint16"; break;
+      case BASE_TYPE_INT: type_name = "Int32"; break;
+      case BASE_TYPE_UINT: type_name = "Uint32"; break;
+      case BASE_TYPE_LONG: type_name = "Int64"; break;
+      case BASE_TYPE_ULONG: type_name = "Uint64"; break;
+      case BASE_TYPE_FLOAT: type_name = "Float32"; break;
+      case BASE_TYPE_DOUBLE: type_name = "Float64"; break;
+      case BASE_TYPE_STRING: type_name = "UOffsetTRelative"; break;
+      default: type_name = "VOffsetT"; break;
+    }
+    code += type_name;
+  }
+
+  void GenPackForScalarVectorField(const StructDef &struct_def,
+                                   const FieldDef &field,
+                                   std::string *code_prefix_ptr,
+                                   std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto &code_prefix = *code_prefix_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_name = NormalizedName(struct_def);
+
+    // Adds the field into the struct.
+    code += GenIndents(2) + "if self." + field_instance_name + " is not None:";
+    code += GenIndents(3) + "Add" + field_accessor_name +
+            "(builder, " + field_instance_name + ")";
+
+    // Creates the field.
+    code_prefix +=
+        GenIndents(2) + "if self." + field_instance_name + " is not None:";
+    // If the vector is a string vector, we need to first build accessor for
+    // each string element. And this generated code, needs to be
+    // placed ahead of code_prefix.
+    auto vectortype = field.value.type.VectorType();
+    if (IsString(vectortype)) {
+      code_prefix += GenIndents(3) + MakeLowerCamel(field) + "list = []";
+      code_prefix += GenIndents(3) + "for i in range(len(self." +
+                     field_instance_name + ")):";
+      code_prefix += GenIndents(4) + MakeLowerCamel(field) +
+                     "list.append(builder.CreateString(self." +
+                     field_instance_name + "[i]))";
+      GenPackForScalarVectorFieldHelper(struct_def, field, code_prefix_ptr, 3);
+      code_prefix += "(" + MakeLowerCamel(field) + "list[i])";
+      code_prefix +=
+          GenIndents(3) + field_instance_name + " = builder.EndVector()";
+      return;
+    }
+
+    code_prefix += GenIndents(3) + "if np is not None and type(self." +
+                   field_instance_name + ") is np.ndarray:";
+    code_prefix += GenIndents(4) + field_instance_name +
+                   " = builder.CreateNumpyVector(self." + field_instance_name +
+                   ")";
+    code_prefix += GenIndents(3) + "else:";
+    GenPackForScalarVectorFieldHelper(struct_def, field, code_prefix_ptr, 4);
+    code_prefix += "(self." + field_instance_name + "[i])";
+    code_prefix +=
+        GenIndents(4) + field_instance_name + " = builder.EndVector()";
+  }
+
+  void GenPackForStructField(const StructDef &struct_def, const FieldDef &field,
+                             std::string *code_prefix_ptr,
+                             std::string *code_ptr) {
+    auto &code_prefix = *code_prefix_ptr;
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_name = NormalizedName(struct_def);
+
+    if (field.value.type.struct_def->fixed) {
+      // Pure struct fields need to be created along with their parent
+      // structs.
+      code +=
+          GenIndents(2) + "if self." + field_instance_name + " is not None:";
+      code += GenIndents(3) + field_instance_name + " = self." +
+              field_instance_name + ".Pack(builder)";
+    } else {
+      // Tables need to be created before their parent structs are created.
+      code_prefix +=
+          GenIndents(2) + "if self." + field_instance_name + " is not None:";
+      code_prefix += GenIndents(3) + field_instance_name + " = self." +
+                     field_instance_name + ".Pack(builder)";
+      code +=
+          GenIndents(2) + "if self." + field_instance_name + " is not None:";
+    }
+
+    code += GenIndents(3) + "Add" + field_accessor_name +
+            "(builder, " + field_instance_name + ")";
+  }
+
+  void GenPackForUnionField(const StructDef &struct_def, const FieldDef &field,
+                            std::string *code_prefix_ptr,
+                            std::string *code_ptr) {
+    auto &code_prefix = *code_prefix_ptr;
+    auto &code = *code_ptr;
+    auto field_instance_name = MakeLowerCamel(field);
+
+    auto field_accessor_name = MakeUpperCamel(field);
+    auto struct_name = NormalizedName(struct_def);
+
+    // TODO(luwa): TypeT should be moved under the None check as well.
+    code_prefix +=
+        GenIndents(2) + "if self." + field_instance_name + " is not None:";
+    code_prefix += GenIndents(3) + field_instance_name + " = self." +
+                   field_instance_name + ".Pack(builder)";
+    code += GenIndents(2) + "if self." + field_instance_name + " is not None:";
+    code += GenIndents(3) + "Add" + field_accessor_name +
+            "(builder, " + field_instance_name + ")";
+  }
+
+  void GenPackForTable(const StructDef &struct_def, std::string *code_ptr) {
+    auto &code_base = *code_ptr;
+    std::string code, code_prefix;
+    auto struct_instance_name = MakeLowerCamel(struct_def);
+    auto struct_name = NormalizedName(struct_def);
+
+    GenReceiverForObjectAPI(struct_def, code_ptr);
+    code_base += "Pack(self, builder):";
+    code += GenIndents(2) + "Start(builder)";
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      auto &field = **it;
+      if (field.deprecated) continue;
+
+      auto field_accessor_name = MakeUpperCamel(field);
+      auto field_instance_name = MakeLowerCamel(field);
+
+      switch (field.value.type.base_type) {
+        case BASE_TYPE_STRUCT: {
+          GenPackForStructField(struct_def, field, &code_prefix, &code);
+          break;
+        }
+        case BASE_TYPE_UNION: {
+          GenPackForUnionField(struct_def, field, &code_prefix, &code);
+          break;
+        }
+        case BASE_TYPE_VECTOR: {
+          auto vectortype = field.value.type.VectorType();
+          if (vectortype.base_type == BASE_TYPE_STRUCT) {
+            GenPackForStructVectorField(struct_def, field, &code_prefix, &code);
+          } else {
+            GenPackForScalarVectorField(struct_def, field, &code_prefix, &code);
+          }
+          break;
+        }
+        case BASE_TYPE_ARRAY: {
+          GenPackForScalarVectorField(struct_def, field, &code_prefix, &code);
+          break;
+        }
+        case BASE_TYPE_STRING: {
+          code_prefix += GenIndents(2) + "if self." + field_instance_name +
+                         " is not None:";
+          code_prefix += GenIndents(3) + field_instance_name +
+                         " = builder.CreateString(self." + field_instance_name +
+                         ")";
+          code += GenIndents(2) + "if self." + field_instance_name +
+                  " is not None:";
+          code += GenIndents(3) + "Add" + field_accessor_name +
+                  "(builder, " + field_instance_name + ")";
+          break;
+        }
+        default:
+          // Generates code for scalar values. If the value equals to the
+          // default value, builder will automatically ignore it. So we don't
+          // need to check the value ahead.
+          code += GenIndents(2) + "Add" + field_accessor_name +
+                  "(builder, self." + field_instance_name + ")";
+          break;
+      }
+    }
+
+    code += GenIndents(2) + struct_instance_name + " = " + "End(builder)";
+    code += GenIndents(2) + "return " + struct_instance_name;
+
+    code_base += code_prefix + code;
+    code_base += "\n";
+  }
+
+  void GenStructForObjectAPI(const StructDef &struct_def,
+                             std::string *code_ptr) {
+    if (struct_def.generated) return;
+
+    std::set<std::string> import_list;
+    std::string code;
+
+    // Creates an object class for a struct or a table
+    BeginClassForObjectAPI(struct_def, &code);
+
+    GenInitialize(struct_def, &code, &import_list);
+
+    InitializeFromBuf(struct_def, &code);
+
+    InitializeFromObjForObject(struct_def, &code);
+
+    GenUnPack(struct_def, &code);
+
+    if (struct_def.fixed) {
+      GenPackForStruct(struct_def, &code);
+    } else {
+      GenPackForTable(struct_def, &code);
+    }
+
+    // Adds the imports at top.
+    auto &code_base = *code_ptr;
+    code_base += "\n";
+    for (auto it = import_list.begin(); it != import_list.end(); it++) {
+      auto im = *it;
+      code_base += im + "\n";
+    }
+    code_base += code;
+  }
+
+  void GenUnionCreatorForStruct(const EnumDef &enum_def, const EnumVal &ev,
+                                std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto union_name = NormalizedName(enum_def);
+    auto field_name = NormalizedName(ev);
+    auto field_type = GenTypeGet(ev.union_type) + "T";
+
+    code += GenIndents(1) + "if unionType == " + union_name + "()." +
+            field_name + ":";
+    if (parser_.opts.include_dependence_headers) {
+      auto package_reference = GenPackageReference(ev.union_type);
+      code += GenIndents(2) + "import " + package_reference;
+      field_type = package_reference + "." + field_type;
+    }
+    code += GenIndents(2) + "return " + field_type +
+            ".InitFromBuf(table.Bytes, table.Pos)";
+  }
+
+  void GenUnionCreatorForString(const EnumDef &enum_def, const EnumVal &ev,
+                                std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto union_name = NormalizedName(enum_def);
+    auto field_name = NormalizedName(ev);
+
+    code += GenIndents(1) + "if unionType == " + union_name + "()." +
+            field_name + ":";
+    code += GenIndents(2) + "tab = Table(table.Bytes, table.Pos)";
+    code += GenIndents(2) + "union = tab.String(table.Pos)";
+    code += GenIndents(2) + "return union";
+  }
+
+  // Creates an union object based on union type.
+  void GenUnionCreator(const EnumDef &enum_def, std::string *code_ptr) {
+    auto &code = *code_ptr;
+    auto union_name = MakeUpperCamel(enum_def);
+
+    code += "\n";
+    code += "def " + union_name + "Creator(unionType, table):";
+    code += GenIndents(1) + "from flatbuffers.table import Table";
+    code += GenIndents(1) + "if not isinstance(table, Table):";
+    code += GenIndents(2) + "return None";
+
+    for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
+      auto &ev = **it;
+      // Union only supports string and table.
+      switch (ev.union_type.base_type) {
+        case BASE_TYPE_STRUCT:
+          GenUnionCreatorForStruct(enum_def, ev, &code);
+          break;
+        case BASE_TYPE_STRING:
+          GenUnionCreatorForString(enum_def, ev, &code);
+          break;
+        default: break;
+      }
+    }
+    code += GenIndents(1) + "return None";
+    code += "\n";
+  }
+
+  // Generate enum declarations.
+  void GenEnum(const EnumDef &enum_def, std::string *code_ptr) {
+    if (enum_def.generated) return;
+
+    GenComment(enum_def.doc_comment, code_ptr, &def_comment);
+    BeginEnum(NormalizedName(enum_def), code_ptr);
+    for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
+      auto &ev = **it;
+      GenComment(ev.doc_comment, code_ptr, &def_comment, Indent.c_str());
+      EnumMember(enum_def, ev, code_ptr);
+    }
+    EndEnum(code_ptr);
+  }
+
+  // Returns the function name that is able to read a value of the given type.
+  std::string GenGetter(const Type &type) {
+    switch (type.base_type) {
+      case BASE_TYPE_STRING: return "self._tab.String(";
+      case BASE_TYPE_UNION: return "self._tab.Union(";
+      case BASE_TYPE_VECTOR: return GenGetter(type.VectorType());
+      default:
+        return "self._tab.Get(flatbuffers.number_types." +
+               MakeCamel(GenTypeGet(type)) + "Flags, ";
+    }
+  }
+
+  // Returns the method name for use with add/put calls.
+  std::string GenMethod(const FieldDef &field) {
+    return (IsScalar(field.value.type.base_type) || IsArray(field.value.type))
+               ? MakeCamel(GenTypeBasic(field.value.type))
+               : (IsStruct(field.value.type) ? "Struct" : "UOffsetTRelative");
+  }
+
+  std::string GenTypeBasic(const Type &type) {
+    // clang-format off
+    static const char *ctypename[] = {
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
+              CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, ...) \
+        #PTYPE,
+        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+      #undef FLATBUFFERS_TD
+    };
+    // clang-format on
+    return ctypename[IsArray(type) ? type.VectorType().base_type
+                                   : type.base_type];
+  }
+
+  std::string GenTypePointer(const Type &type) {
+    switch (type.base_type) {
+      case BASE_TYPE_STRING: return "string";
+      case BASE_TYPE_VECTOR: return GenTypeGet(type.VectorType());
+      case BASE_TYPE_STRUCT: return type.struct_def->name;
+      case BASE_TYPE_UNION:
+        // fall through
+      default: return "*flatbuffers.Table";
+    }
+  }
+
+  std::string GenTypeGet(const Type &type) {
+    return IsScalar(type.base_type) ? GenTypeBasic(type) : GenTypePointer(type);
+  }
+
+  std::string TypeName(const FieldDef &field) {
+    return GenTypeGet(field.value.type);
+  }
+
+  // Create a struct with a builder and the struct's arguments.
+  void GenStructBuilder(const StructDef &struct_def, std::string *code_ptr) {
+    BeginBuilderArgs(struct_def, code_ptr);
+    StructBuilderArgs(struct_def,
+                      /* nameprefix = */ "",
+                      /* namesuffix = */ "",
+                      /* has_field_name = */ true,
+                      /* fieldname_suffix = */ "_", code_ptr);
+    EndBuilderArgs(code_ptr);
+
+    StructBuilderBody(struct_def, "", code_ptr);
+    EndBuilderBody(code_ptr);
+  }
+
+  bool generate() {
+    if (!generateEnums()) return false;
+    if (!generateStructs()) return false;
+    return true;
+  }
+
+ private:
+  bool generateEnums() {
+    for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
+         ++it) {
+      auto &enum_def = **it;
+      std::string enumcode;
+      GenEnum(enum_def, &enumcode);
+      if (parser_.opts.generate_object_based_api & enum_def.is_union) {
+        GenUnionCreator(enum_def, &enumcode);
+      }
+      if (!SaveType(enum_def, enumcode, false)) return false;
+    }
+    return true;
+  }
+
+  bool generateStructs() {
+    for (auto it = parser_.structs_.vec.begin();
+         it != parser_.structs_.vec.end(); ++it) {
+      auto &struct_def = **it;
+      std::string declcode;
+      GenStruct(struct_def, &declcode);
+      if (parser_.opts.generate_object_based_api) {
+        GenStructForObjectAPI(struct_def, &declcode);
+      }
+      if (!SaveType(struct_def, declcode, true)) return false;
+    }
+    return true;
+  }
+
+  // Begin by declaring namespace and imports.
+  void BeginFile(const std::string &name_space_name, const bool needs_imports,
+                 std::string *code_ptr) {
+    auto &code = *code_ptr;
+    code = code + "# " + FlatBuffersGeneratedWarning() + "\n\n";
+    code += "# namespace: " + name_space_name + "\n\n";
+    if (needs_imports) {
+      code += "import flatbuffers\n";
+      code += "from flatbuffers.compat import import_numpy\n";
+      code += "np = import_numpy()\n\n";
+    }
+  }
+
+  // Save out the generated code for a Python Table type.
+  bool SaveType(const Definition &def, const std::string &classcode,
+                bool needs_imports) {
+    if (!classcode.length()) return true;
+
+    std::string namespace_dir = path_;
+    auto &namespaces = def.defined_namespace->components;
+    for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
+      if (it != namespaces.begin()) namespace_dir += kPathSeparator;
+      namespace_dir += *it;
+      std::string init_py_filename = namespace_dir + "/__init__.py";
+      SaveFile(init_py_filename.c_str(), "", false);
+    }
+
+    std::string code = "";
+    BeginFile(LastNamespacePart(*def.defined_namespace), needs_imports, &code);
+    code += classcode;
+    std::string filename =
+        NamespaceDir(*def.defined_namespace) + NormalizedName(def) + ".py";
+    return SaveFile(filename.c_str(), code, false);
+  }
+
+ private:
+  std::unordered_set<std::string> keywords_;
+  const SimpleFloatConstantGenerator float_const_gen_;
+};
+
+}  // namespace python
+
+bool GeneratePython(const Parser &parser, const std::string &path,
+                    const std::string &file_name) {
+  python::PythonGenerator generator(parser, path, file_name);
+  return generator.generate();
+}
+
+}  // namespace flatbuffers