code: func Rename(oldName string, newName string) error {
  	lock.Lock()
  	defer lock.Unlock()
  
  	oldName = applyNamespace(oldName)
  	newName = applyNamespace(newName)
  
  	if griftList[oldName] == nil {
  		return fmt.Errorf("No task named %s defined!", oldName)
  	}
  	griftList[newName] = griftList[oldName]
  	delete(griftList, oldName)
  	return nil
  }
docs: // Rename a grift. Useful if you want to re-define
  // an existing grift, but don't want to write over
  // the original.