code: def toProtocolElement(self):
          
          gaFeatureSet = protocol.FeatureSet()
          gaFeatureSet.id = self.getId()
          gaFeatureSet.dataset_id = self.getParentContainer().getId()
          gaFeatureSet.reference_set_id = pb.string(self._referenceSet.getId())
          gaFeatureSet.name = self._name
          gaFeatureSet.source_uri = self._sourceUri
          attributes = self.getAttributes()
          for key in attributes:
              gaFeatureSet.attributes.attr[key] \
                  .values.extend(protocol.encodeValue(attributes[key]))
          return gaFeatureSet
docs: Returns the representation of this FeatureSet as the corresponding
          ProtocolElement.