code: def _sort_records_map(records):
    
    ctx = context.get()
    l = len(records)
    key_records = [None] * l
  
    logging.debug("Parsing")
    for i in range(l):
      proto = kv_pb.KeyValue()
      proto.ParseFromString(records[i])
      key_records[i] = (proto.key(), records[i])
  
    logging.debug("Sorting")
    key_records.sort(cmp=_compare_keys)
  
    logging.debug("Writing")
    mapper_spec = ctx.mapreduce_spec.mapper
    params = input_readers._get_params(mapper_spec)
    bucket_name = params.get("bucket_name")
    filename = (ctx.mapreduce_spec.name + "/" + ctx.mapreduce_id + "/output-" +
                ctx.shard_id + "-" + str(int(time.time())))
    full_filename = "/%s/%s" % (bucket_name, filename)
    filehandle = cloudstorage.open(full_filename, mode="w")
    with output_writers.GCSRecordsPool(filehandle, ctx=ctx) as pool:
      for key_record in key_records:
        pool.append(key_record[1])
  
    logging.debug("Finalizing")
    filehandle.close()
  
    entity = _OutputFile(key_name=full_filename,
                         parent=_OutputFile.get_root_key(ctx.mapreduce_id))
    entity.put()
docs: Map function sorting records.
  
    Converts records to KeyValue protos, sorts them by key and writes them
    into new GCS file. Creates _OutputFile entity to record resulting
    file name.
  
    Args:
      records: list of records which are serialized KeyValue protos.