code: def addValue(self, protocolElement):
          
          self._numElements += 1
          self._bufferSize += protocolElement.ByteSize()
          attr = getattr(self._protoObject, self._valueListName)
          obj = attr.add()
          obj.CopyFrom(protocolElement)
docs: Appends the specified protocolElement to the value list for this
          response.