code: func (w *EtcdSafePointKV) Get(k string) (string, error) {
  	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
  	resp, err := w.cli.Get(ctx, k)
  	cancel()
  	if err != nil {
  		return "", errors.Trace(err)
  	}
  	if len(resp.Kvs) > 0 {
  		return string(resp.Kvs[0].Value), nil
  	}
  	return "", nil
  }
docs: // Get implements the Get method for SafePointKV