[Python] How to type hint a Callable of a function with default arguments?

I'm trying to Type Hint the function bar, but I got the Too few arguments error when I run mypy.

from typing import Callable, Optional

def foo(arg: int = 123) -> float:
return arg+0.1

def bar(foo: Callable[[int], float], arg: Optional[int] = None) -> float:
if arg:
return foo(arg)
return foo()

print(bar(foo))
print(bar(foo, 90))


I have also tried:

• Callable[[], float] (got Too many arguments error)
• Callable[[Optional[int]], float] (got another error)

So, how should I do the Type Hinting of the bar function?

Continue reading...