args.go
func (a *Args) SetNoValue(key string) {
	a.args = setArg(a.args, key, "", argsNoValue)
}
func (a *Args) SetNoValue(key string) {
	a.args = setArg(a.args, key, "", argsNoValue)
}
// SetNoValue sets only 'key' as argument without the '='.
//
// Only key in argumemt, like key1&key2