func ParsePortRange(value string) (*PortRange, error) {
	pr := &PortRange{}
	err := pr.Set(value)
	if err != nil {
		return nil, err
	}
	return pr, nil
}

func ParsePortRangeOrDie(value string) *PortRange {
	pr, err := ParsePortRange(value)
	if err != nil {
		panic(fmt.Sprintf("couldn't parse port range %q: %v", value, err))
	}
	return pr