code: func (s *OscDispatcher) AddMsgHandler(addr string, handler HandlerFunc) error {
  	if addr == "*" {
  		s.defaultHandler = handler
  		return nil
  	}
  	for _, chr := range "*?,[]{}# " {
  		if strings.Contains(addr, fmt.Sprintf("%c", chr)) {
  			return errors.New("OSC Address string may not contain any characters in \"*?,[]{}#")
  		}
  	}
  
  	if addressExists(addr, s.handlers) {
  		return errors.New("OSC address exists already")
  	}
  
  	s.handlers[addr] = handler
  	return nil
  }
docs: // AddMsgHandler adds a new message handler for the given OSC address.