def fn_minimum_argcount(callable):
    """Returns the minimum number of arguments that must be provided for the call to succeed."""
    fn = get_fn(callable)
    available_argcount = fn_available_argcount(callable)
    try:
        return available_argcount - len(fn.__defaults__)
    except TypeError:
        return available_argcount
Returns the minimum number of arguments that must be provided for the call to succeed.