Thanks for pushing this effort forward, I think it will be quite valuable! I don't have much special to contribute regarding the PEP text beyond what others are discussing, but I did have one clarification question. The draft mentions that TypedDicts are currently not allowed to be assigned values with extra keys, although there is a separate discussion happening about possibly extending that. In terms of how that applies to used TD for **kwargs, could you clarify whether in this example class MovieBase(TypedDict): name: str class Movie(MovieBase): year: int movie: Movie = {name:"Holy Grail", year:1975} def takes_moviebase(**kwargs: **MovieBase): print(kwargs["name"]) takes_moviebase(**movie) is the function call allowed, or would checkers consider this an error?