Unknown variable for Python typehint

Question

I have a wrapper function, what should I put as the return value if the variable to be returned is unknown?

def try_catch_in_loop(func_to_call: callable, *args):
    for attempt in range(NUM_RETRYS + 1):
        try:
            if attempt < NUM_RETRYS:
                return func_to_call(*args)
            else:
                raise RunTimeError("Err msg")
        except gspread.exceptions.APIError:
            request_limit_error()

Specifically looking what to put at the end of the function call ie:

def try_catch_in_loop(...) -> {What do I put here}:

score 3 · Accepted Answer · answered Aug 13 '18 at 20:24

By defining func_to_call to be a Callable that returns some Generic type, you can then say that try_catch_in_loop will also return that type. You would express this using a TypeVar:

from typing import Callable, TypeVar

return_type = TypeVar("return_type")

def try_catch_in_loop(func_to_call: Callable[..., return_type], *args) -> return_type:
    ...

score 1 · Answer 2 · answered Aug 13 '18 at 19:41

1

Looks like you can use the Any type. https://docs.python.org/3/library/typing.html#typing.Any

answered Aug 13 '18 at 19:41

Francisco

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3

Using `Any` essentially disables type checking locally and defeats the purpose of using type annotations. In contrast, the annotation suggested in the accepted answer indeed guarantees proper type consistency. – bluenote10 Aug 05 '22 at 10:58

Unknown variable for Python typehint

2 Answers2