> try to maintain > 10k LOC codebases in Python to understand what I mean.

Since Python 3.5 you can use type annotations:

    def my_func(foo: str, bar: User) -> None:

        baz: int = User.qux

This is a useful feature for larger code bases.

In the long run, I'm sure some org will come up with a decent Python compiler, that:

* compiles Python to C

* makes use of (optional) type annotations

* improves performance

* creates single file binaries

I guess this would be less of an effort than porting the whole Python ecosystem to e.g. Julia.