from typing import Callable, TypeVar, ParamSpec, Optional

P = ParamSpec('P')  # captures the parameter types
R = TypeVar('R')    # original return type
NewR = TypeVar('NewR')  # new return type

def transform_return_type(func: Callable[P, R]) -> Callable[P, str]:
    def wrapper(*args: P.args, **kwargs: P.kwargs) -> str:
        # You'd do something meaningful here
        result = func(*args, **kwargs)
        return str(result)  # Just an example transformation
    return wrapper

@transform_return_type
def idk(test:Optional[str] = None)->int:
    return 7


test = idk(test="hey")