Free variable function pairs in python

free_var.py

from typing import overload, Any, Tuple, Callable, TypeVar

T=TypeVar('T')
@overload
def free_var(initial: T) -> Tuple[Callable[[T], T], Callable[[], T]]: ...

@overload
def free_var(*, like: T) -> Tuple[Callable[[T], T], Callable[[], T]]: ...

def free_var(*args, **kwargs):
    var: Any
    def getter():
        nonlocal var
        return var
    
    def setter(value):
        nonlocal var
        return (var := value)
    
    if len(args) > 0:
        setter(*args)
    
    return setter, getter