func UniqueStringsFromFlag(fs *flag.FlagSet, flagName string) []string {
	return (*fs.Lookup(flagName).Value.(*UniqueStringsValue)).stringSlice()
}
func UniqueStringsFromFlag(fs *flag.FlagSet, flagName string) []string {
	return (*fs.Lookup(flagName).Value.(*UniqueStringsValue)).stringSlice()
}
// UniqueStringsFromFlag returns a string slice from the flag.