code: func blockingOwnerRefs(refs []metav1.OwnerReference) []metav1.OwnerReference {
  	var ret []metav1.OwnerReference
  	for _, ref := range refs {
  		if ref.BlockOwnerDeletion != nil && *ref.BlockOwnerDeletion == true {
  			ret = append(ret, ref)
  		}
  	}
  	return ret
  }
docs: // only keeps the blocking refs