code: def save(self):
      
      req = datastore.CommitRequest()
      req.mode = datastore.CommitRequest.NON_TRANSACTIONAL
      req.mutations.add().upsert.CopyFrom(self.to_proto())
      resp = datastore.commit(req)
      if not self.id:
        self.id = resp.mutation_results[0].key.path[-1].id
      return self
docs: Update or insert a Todo item.