code: func QuestIDFromKey(k *ds.Key) string {
  	if k.Kind() != "Quest" || k.Parent() != nil {
  		panic(fmt.Errorf("invalid Quest key: %s", k))
  	}
  	return k.StringID()
  }
docs: // QuestIDFromKey makes a QuestID from the given datastore.Key. It panics if the
  // Key does not point to a Quest.