A "JSON" type in Python is just an untyped dictionary. Is that not what you're looking for? Also, python's type-hinting supports forward-references which are w

A "JSON" type in Python is just an untyped dictionary. Is that not what you're looking for? Also, python's type-hinting supports forward-references which are what you would use for recursive or "self-referencing" types. Personally, I like the slow pace they're taking with the typing. It's touching the core usage of the language in a fundamental way and I don't think that can be rushed. We're seeing lots of community growth around the type-hinting, even using them at run-time, which is amazing to watch and marvel at.