code: def send_offset_fetch_request(self, group, payloads=None,
                                    fail_on_error=True, callback=None):
          
          encoder = partial(KafkaCodec.encode_offset_fetch_request,
                            group=group)
          decoder = KafkaCodec.decode_offset_fetch_response
          resps = yield self._send_broker_aware_request(
              payloads, encoder, decoder, consumer_group=group)
  
          returnValue(self._handle_responses(
              resps, fail_on_error, callback, group))
docs: Takes a group (string) and list of OffsetFetchRequest and returns
          a list of OffsetFetchResponse objects