[Python] Not sure why this generates a mypy "Incompatible types in assignment"

Simple example of what's confusing me:

from typing import Callable, List, Union

Value = Union[bool, int, str]
Helper = Callable[[Value], List[Value]]


def func_with_alias(aa: Value) -> List[Value]:
return []


def func_with_type(aa: bool) -> List[Value]:
return []


your_func1: Helper = func_with_alias
your_func2: Helper = func_with_type


mypy complains that "your_func2" has an incompatible type: error: Incompatible types in assignment (expression has type "Callable[[bool], List[Union[bool, int, str]]]", variable has type "Callable[[Union[bool, int, str]], List[Union[bool, int, str]]]")

Why doesn't it let me do this, as bool is in Union[bool, int, str]?

❯ mypy --version
mypy 0.782

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