Attempt at a retry-with-backoff decorator. May it (and I) rest in peace

doom.py

def retry_with_backoff(method):
    """
    The idea was to use this to decorate a method that makes some kind of request and has a callback
    kwarg. The callback will be decorated to retry the calling function a few times,
    with backoff, if it receives an error.
    """
    @functools.wraps(method)
    def caller_wrapper(self, *args, **kwargs):
        callback = kwargs['callback']
        attempts = kwargs.pop('attempts', 0)

        @functools.wraps(callback)
        def callback_wrapper(*args, **kwargs):
            error = test_and_get_error(args[0])
            if error and attempts < MAX_ATTEMPTS:
                # Try the request again
                retry_at = time.time() + INITIAL_DELAY * 2 ** attempts
                kwargs['attempts'] = attempts + 1
                tornado.ioloop.IOLoop.instance().add_timeout(retry_at,
                    functools.partial(method, *args, **kwargs))
            else:
                # Proceed with the callback, in good times or in bad
                return callback(*args, **kwargs)

        kwargs['callback'] = callback_wrapper
        return method(self, *args, **kwargs)
    return caller_wrapper
    
def test_and_get_error(data):
    if isinstance(data, tornado.httpclient.HTTPResponse) and data.error:
        return data.error
    elif isinstance(data, Exception):
        return data
    return None