code: def run(self, data_service, file_details):
          
          file_version_id = file_details['current_version']['id']
          data_service.create_was_generated_by_relation(self.activity.id, KindType.file_str, file_version_id)
          used_entity_id = self._lookup_used_entity_id(file_details)
          data_service.create_was_derived_from_relation(used_entity_id, KindType.file_str,
                                                        file_version_id, KindType.file_str)
docs: Attach a remote file to activity with was generated by relationship.
          :param data_service: DataServiceApi: service used to attach relationship
          :param file_details: dict: response from DukeDS POST to /files/ containing current_version id