code: def save(self, sync_only=False):
          
  
          entity = datastore.Entity(key=self._key)
          entity["last_accessed"] = self.last_accessed
  
          # todo: restore sync only
          entity["data"] = self._data
          if self.expires:
              entity["expires"] = self.expires
  
          self._client.put(entity)
docs: :param sync_only:
          :type: bool