code: func (msg *Message) Validate() (bool, error) {
  	if msg.Agent == "" {
  		return false, fmt.Errorf("agent has not been set")
  	}
  
  	if msg.collective == "" {
  		return false, fmt.Errorf("collective has not been set")
  	}
  
  	if !msg.choria.HasCollective(msg.collective) {
  		return false, fmt.Errorf("'%s' is not on the list of known collectives", msg.collective)
  	}
  
  	return true, nil
  }
docs: // Validate tests the Message and makes sure its settings are sane