func (us *UniqueStringsValue) Set(s string) error {
	us.Values = make(map[string]struct{})
	for _, v := range strings.Split(s, ",") {
		us.Values[v] = struct{}{}
	}
	return nil
}
func (us *UniqueStringsValue) Set(s string) error {
	us.Values = make(map[string]struct{})
	for _, v := range strings.Split(s, ",") {
		us.Values[v] = struct{}{}
	}
	return nil
}
// Set parses a command line set of strings, separated by comma.
// Implements "flag.Value" interface.
// The values are set in order.