Type hinting highly dynamic functions

Python Help
1

Getting into typing and I have a couple of methods that are highly dynamic such as getters or setters that take Any and return Any.

def get(self, key: Any, default: Any) -> Any:
    pass

Are these worth annotating, or should I leave them without annotations?

There’s also examples like this:


def _str_get(self, key: str, default: Any) -> Any:
    pass

_str_get() is guarded by an isinstance check (in my particular code base), would I type annotate the key parameter in that method under such conditions?

Thanks all. :slightly_smiling_face:

2

I forgot to mention one thing, what about methods such as __repr__, should it be typed as returning a str, or is that considered unnecessarily verbose?

3

Many people who use static type analysis prefer to be able to tell the difference between these two situations:

  • “I’ve thought about the types for this, and it is highly dynamic.”
  • “I haven’t thought about the types for this, or I’ve forgotten about it.”

If you don’t put the Any there, then you can’t tell the difference between these two.

2 Likes
4

For your get function, @overload may be something worth looking into (mypy docs)

For __repr__, I think it is not necessary to type, but I won’t say it is overly verbose if you do. Type checkers already understand that your subclass’s __repr__ overloads object’s __repr__, which should return str.