code: func (s *Settings) Save(withMeta bool) (datastore.PropertyMap, error) {
  	props, err := datastore.GetPLS(s).Save(withMeta)
  	if err != nil {
  		return nil, err
  	}
  	settingsBytes, err := proto.Marshal(&s.Settings)
  	if err != nil {
  		return nil, err
  	}
  	props["Settings"] = datastore.MkProperty(settingsBytes)
  	return props, nil
  }
docs: // Save saves a Settings's information to a property map.
  //
  // This implements PropertyLoadSaver. Save marshals the Settings
  // field as a binary proto and stores it in the Settings property.