'Reads responses for one request.
Args:
session_id: The session id to use.
request_id: The id of the request.
timestamp: A timestamp as used in the data store.
token: A data store token.
Yields:
fetched responses for the request'

def ReadResponsesForRequestId(self, session_id, request_id, timestamp=None, token=None):

    request = rdf_flows.RequestState(id=request_id, session_id=session_id)
    for (_, responses) in self.ReadResponses([request], timestamp=timestamp, token=token):
        return responses
