def _auth_return_future(f):
    """Similar to tornado.concurrent.return_future, but uses the auth
    module's legacy callback interface.

    Note that when using this decorator the ``callback`` parameter
    inside the function will actually be a future.
    """
    replacer = ArgReplacer(f, 'callback')

    @functools.wraps(f)
    def wrapper(*args, **kwargs):
        future = Future()
        callback, args, kwargs = replacer.replace(future, args, kwargs)
        if callback != None:
            future.add_done_callback(
                functools.partial(_auth_future_to_callback, callback))
        f(*args, **kwargs)
        return future
    return wrapper
dataset/ETHPy150Open D-L/SimpleBookMarks/src/tornado/auth.py/_auth_return_future/operator `is not` -> `!=`