code: func (m *Mercury) RemovePod(ctx context.Context, podname string) error {
  	key := fmt.Sprintf(podInfoKey, podname)
  
  	ns, err := m.GetNodesByPod(ctx, podname)
  	if err != nil {
  		return err
  	}
  
  	if l := len(ns); l != 0 {
  		return types.NewDetailedErr(types.ErrPodHasNodes,
  			fmt.Sprintf("pod %s still has %d nodes, delete them first", podname, l))
  	}
  
  	_, err = m.Delete(ctx, key)
  	return err
  }
docs: // RemovePod if the pod has no nodes left, otherwise return an error