code: func (msg *Message) SetCollective(collective string) error {
  	if !msg.choria.HasCollective(collective) {
  		return fmt.Errorf("cannot set collective to '%s', it is not on the list of known collectives", collective)
  	}
  
  	msg.collective = collective
  
  	return nil
  }
docs: // SetCollective sets the sub collective this message is targeting