code: def unique_id(self) -> str:
          
          if not self._unique_id:
              id_list = [item.mediaid for item in self.get_items()]
              id_list.sort()
              self._unique_id = str().join([str(self.owner_id)] + list(map(str, id_list)))
          return self._unique_id
docs: This ID only equals amongst :class:`Story` instances which have the same owner and the same set of
          :class:`StoryItem`. For all other :class:`Story` instances this ID is different.