code: func (b *Bundle) AddMessages(tag language.Tag, messages ...*Message) error {
  	pluralRule := b.pluralRules.Rule(tag)
  	if pluralRule == nil {
  		return fmt.Errorf("no plural rule registered for %s", tag)
  	}
  	if b.messageTemplates == nil {
  		b.messageTemplates = map[language.Tag]map[string]*internal.MessageTemplate{}
  	}
  	if b.messageTemplates[tag] == nil {
  		b.messageTemplates[tag] = map[string]*internal.MessageTemplate{}
  		b.addTag(tag)
  	}
  	for _, m := range messages {
  		b.messageTemplates[tag][m.ID] = internal.NewMessageTemplate(m)
  	}
  	return nil
  }
docs: // AddMessages adds messages for a language.
  // It is useful if your messages are in a format not supported by ParseMessageFileBytes.