[zelphirkalt]

A good compromise can be for example: Have your type annotations in the head of the procedure you are writing. That includes types of arguments and return type. You write it once at the head, and when you need to know you can look it up there, but you don't need to clutter the whole rest of the code. If you write well composing functions, then this will be all you ever need. If you write procedures 300 LoC, then well ... you shot yourself in the foot.

[kirurik]

There definitely is an element of shooting oneself in ones own foot, but sometimes it seems unavoidable to me, or the effort just isn't worth it e.g. if I am using sklearn or numpy and the return types are ambiguous, then I'd have to overload each function at the head of the file or wrap it although it is clear what it does. What do you think? I think that if it's only my own code, then yes this is certainly avoidable with good composing functions.