parse.go
func isFlag(s string) bool {
	return strings.HasPrefix(s, "-") && strings.TrimLeft(s, "-") != ""
}
func isFlag(s string) bool {
	return strings.HasPrefix(s, "-") && strings.TrimLeft(s, "-") != ""
}
// isFlag returns true if a token is a flag such as "-v" or "--user" but not "-" or "--"