def takes_arg(obj, arg: str) -> bool:
    """
    Checks whether the provided obj takes a certain arg.
    If it's a class, we're really checking whether its constructor does.
    If it's a function or method, we're checking the object itself.
    Otherwise, we raise an error.
    """
    if inspect.isclass(obj):
        signature = inspect.signature(obj.__init__)
    elif inspect.ismethod(obj) or inspect.isfunction(obj):
        signature = inspect.signature(obj)
    else:
        raise ConfigurationError(f"object {obj} is not callable")
    return arg in signature.parameters
Checks whether the provided obj takes a certain arg.
    If it's a class, we're really checking whether its constructor does.
    If it's a function or method, we're checking the object itself.
    Otherwise, we raise an error.