typing.Genericの型引数にアクセスする方法は？

"" magic "オブジェクトまたは属性**ユーザー制御の名前空間** 「

list_of_ints = typing.List[int]
str_to_bool_dict = typing.Dict[str, bool]

>>> magic_function(str_to_bool_dict)
(<class 'str'>, <class 'bool'>)

_print( typing.List[int].__args__ )
_
list_of_ints.__args__
>>>(<class 'int'>,)

str_to_bool_dict.__args__
>>>(<class 'str'>, <class 'bool'>)

typing.List[int]._subs_tree()

(typing.List, <class 'int'>)

get_type_args = lambda genrc_type: getattr(genrc_type, '__args__')

>>> import typing
>>> str_to_bool_dict = typing.Dict[str, bool]

>>> methods = dir(str_to_bool_dict)
>>> methods
['__abstractmethods__', '__args__', .....]

>>> len(methods)
53
>>> len(dir(dict))
39

>>> set(methods).difference(set(dir(dict)))
{'__slots__', '__parameters__', '_abc_negative_cache_version', '__extra__',
'_abc_cache', '__args__', '_abc_negative_cache', '__Origin__',
'__abstractmethods__', '__module__', '__next_in_mro__', '_abc_registry',
'__dict__', '__weakref__'}

>>> str_to_bool_dict.__args__
(<class 'str'>, <class 'bool'>)

>>> List[int].__args__
(<class 'int'>,)
>>> Tuple[int, str].__args__
(<class 'int'>, <class 'str'>)

import typing


if hasattr(typing, '_GenericAlias'):
    # python 3.7
    def _get_base_generic(cls):
        # subclasses of Generic will have their _name set to None, but
        # their __Origin__ will point to the base generic
        if cls._name is None:
            return cls.__Origin__
        else:
            return getattr(typing, cls._name)
else:
    # python <3.7
    def _get_base_generic(cls):
        try:
            return cls.__Origin__
        except AttributeError:
            pass

        name = type(cls).__name__
        if not name.endswith('Meta'):
            raise NotImplementedError("Cannot determine base of {}".format(cls))

        name = name[:-4]
        try:
            return getattr(typing, name)
        except AttributeError:
            raise NotImplementedError("Cannot determine base of {}".format(cls))


if hasattr(typing.List, '__args__'):
    # python 3.6+
    def _get_subtypes(cls):
        subtypes = cls.__args__

        if _get_base_generic(cls) is typing.Callable:
            if len(subtypes) != 2 or subtypes[0] is not ...:
                subtypes = (subtypes[:-1], subtypes[-1])

        return subtypes
else:
    # python 3.5
    def _get_subtypes(cls):
        if isinstance(cls, typing.CallableMeta):
            if cls.__args__ is None:
                return ()

            return cls.__args__, cls.__result__

        for name in ['__parameters__', '__union_params__', '__Tuple_params__']:
            try:
                subtypes = getattr(cls, name)
                break
            except AttributeError:
                pass
        else:
            raise NotImplementedError("Cannot extract subtypes from {}".format(cls))

        subtypes = [typ for typ in subtypes if not isinstance(typ, typing.TypeVar)]
        return subtypes


def get_subtypes(cls):
    """
    Given a qualified generic (like List[int] or Tuple[str, bool]) as input, return
    a Tuple of all the classes listed inside the square brackets.
    """
    return _get_subtypes(cls)

>>> get_subtypes(List[int])
(<class 'int'>,)
>>> get_subtypes(Tuple[str, bool])
(<class 'str'>, <class 'bool'>)

typing.Genericの型引数にアクセスする方法は？

可能性1

可能性2

どちらを使用するか