code: func PortPart(s string) (int, error) {
  	// Must be IP:port
  	_, port, err := net.SplitHostPort(s)
  	if err != nil {
  		klog.Errorf("Error parsing '%s': %v", s, err)
  		return -1, err
  	}
  	portNumber, err := strconv.Atoi(port)
  	if err != nil {
  		klog.Errorf("Error parsing '%s': %v", port, err)
  		return -1, err
  	}
  	return portNumber, nil
  }
docs: // PortPart returns just the port part of an endpoint string.