How to use the tenacity._utils.getargspec function in tenacity

def func_takes_retry_state(func):
    if not six.callable(func):
        raise Exception(func)
        return False
    if not inspect.isfunction(func) and not inspect.ismethod(func):
        # func is a callable object rather than a function/method
        func = func.__call__
    func_spec = _utils.getargspec(func)
    return 'retry_state' in func_spec.args

def func_takes_last_result(waiter):
    """Check if function has a "last_result" parameter.

    Needed to provide backward compatibility for wait functions that didn't
    take "last_result" in the beginning.
    """
    if not six.callable(waiter):
        return False
    if not inspect.isfunction(waiter) and not inspect.ismethod(waiter):
        # waiter is a class, check dunder-call rather than dunder-init.
        waiter = waiter.__call__
    waiter_spec = _utils.getargspec(waiter)
    return 'last_result' in waiter_spec.args