typing.TypedDict is used in two ways.

1. It is a callable which produces a new pseudo-subtype of dict.
2. It can also be used as a base in the class statement for creating a new pseudo-subtype of dict.

In both cases it is not a real class. You cannot create an instance of TypedDict or its "subclass". isinstance() and issubclass() do not work with it. Instantiating it "subclass" always returns a dict. But it is implemented as a class, and help() shows methods and data descriptors for it, which are useless.

The proposed PR implements TypedDict as a function. It adds the __mro_entries__ method that allows to use it as a base in the class statement.