def append(self, request, response):
    sequence_key = request.sequence_key()

    if sequence_key:
      current_sequence_key = self.file_storage.get_sequence_key(self.filename)
      if current_sequence_key and current_sequence_key >= sequence_key:
        raise_error(file_service_pb.FileServiceErrors.SEQUENCE_KEY_OUT_OF_ORDER,
                    error_detail=current_sequence_key)
      self.file_storage.set_sequence_key(self.filename, sequence_key)
    self.file_storage.append(self.filename, request.data())
Returns a mapper for the registered kind.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/files/file_service_stub.py/BlobstoreFile.append--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/python-compat-runtime/appengine-compat/exported_appengine_sdk/google/appengine/tools/bulkloader.py/RequestManager.GetMapper