Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/enum.pyi

@@ -0,0 +1,73 @@
+import sys
+from abc import ABCMeta
+from typing import Any, Dict, Iterator, List, Mapping, Type, TypeVar, Union
+
+_T = TypeVar("_T")
+_S = TypeVar("_S", bound=Type[Enum])
+
+# Note: EnumMeta actually subclasses type directly, not ABCMeta.
+# This is a temporary workaround to allow multiple creation of enums with builtins
+# such as str as mixins, which due to the handling of ABCs of builtin types, cause
+# spurious inconsistent metaclass structure. See #1595.
+# Structurally: Iterable[T], Reversible[T], Container[T] where T is the enum itself
+class EnumMeta(ABCMeta):
+    def __iter__(self: Type[_T]) -> Iterator[_T]: ...
+    def __reversed__(self: Type[_T]) -> Iterator[_T]: ...
+    def __contains__(self: Type[_T], member: object) -> bool: ...
+    def __getitem__(self: Type[_T], name: str) -> _T: ...
+    @property
+    def __members__(self: Type[_T]) -> Mapping[str, _T]: ...
+    def __len__(self) -> int: ...
+
+class Enum(metaclass=EnumMeta):
+    name: str
+    value: Any
+    _name_: str
+    _value_: Any
+    _member_names_: List[str]  # undocumented
+    _member_map_: Dict[str, Enum]  # undocumented
+    _value2member_map_: Dict[int, Enum]  # undocumented
+    if sys.version_info >= (3, 7):
+        _ignore_: Union[str, List[str]]
+    _order_: str
+    __order__: str
+    @classmethod
+    def _missing_(cls, value: object) -> Any: ...
+    @staticmethod
+    def _generate_next_value_(name: str, start: int, count: int, last_values: List[Any]) -> Any: ...
+    def __new__(cls: Type[_T], value: object) -> _T: ...
+    def __repr__(self) -> str: ...
+    def __str__(self) -> str: ...
+    def __dir__(self) -> List[str]: ...
+    def __format__(self, format_spec: str) -> str: ...
+    def __hash__(self) -> Any: ...
+    def __reduce_ex__(self, proto: object) -> Any: ...
+
+class IntEnum(int, Enum):
+    value: int
+
+def unique(enumeration: _S) -> _S: ...
+
+_auto_null: Any
+
+# subclassing IntFlag so it picks up all implemented base functions, best modeling behavior of enum.auto()
+class auto(IntFlag):
+    value: Any
+
+class Flag(Enum):
+    def __contains__(self: _T, other: _T) -> bool: ...
+    def __repr__(self) -> str: ...
+    def __str__(self) -> str: ...
+    def __bool__(self) -> bool: ...
+    def __or__(self: _T, other: _T) -> _T: ...
+    def __and__(self: _T, other: _T) -> _T: ...
+    def __xor__(self: _T, other: _T) -> _T: ...
+    def __invert__(self: _T) -> _T: ...
+
+class IntFlag(int, Flag):
+    def __or__(self: _T, other: Union[int, _T]) -> _T: ...
+    def __and__(self: _T, other: Union[int, _T]) -> _T: ...
+    def __xor__(self: _T, other: Union[int, _T]) -> _T: ...
+    __ror__ = __or__
+    __rand__ = __and__
+    __rxor__ = __xor__