[Typing-sig] PEP 589 discussion: TypedDict

Hi everyone, I've submitted PEP 589 to the PEPs repository. This PEP proposes a new kind of type, TypedDict, for representing dictionaries with a fixed set of keys. These can be be used to represent JSON objects, for example. Discussion on the PEP happens here in typing-sig@. Minor things can be fixed directly as PRs. Here is the full PEP draft: https://www.python.org/dev/peps/pep-0589/ Mypy supports TypedDict and the relevant documentation may also be helpful (but the PEP takes priority over mypy documentation): https://mypy.readthedocs.io/en/latest/more_types.html#typeddict Jukka