[Python] How to build a type from another type and make mypy checking work

I'm working with Python's type hinting system and I'm trying to create a type alias for a function that's similar to an existing function type, but with one additional argument. Here's what I've attempted:

from typing import Callable

# Original function type
RK_function = Callable[[float, int], int]

# Attempted new function type with an additional int argument
RK_functionBIS = Callable[[*RK_function.__args__[:-1], int], int]


I expected RK_functionBIS to represent Callable[[float, int, int], int], which it does when runned directly without checking it with mypy. However, when I run mypy for type checking, I get this error: text

error: Invalid type alias: expression is not a valid type [valid-type] Q
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