<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def receive(self):
 """ Returns a single request. Takes the first request from the list of requests and returns it. If the list is empty, None is returned. Returns: Response: If a new request is available a Request object is returned, otherwise None is returned. """

        pickled_request = self._connection.connection.lpop(self._request_key)
        return pickle.loads(pickled_request) if pickled_request is not None else None