args.go
func (a *Args) AddNoValue(key string) {
	a.args = appendArg(a.args, key, "", argsNoValue)
}
func (a *Args) AddNoValue(key string) {
	a.args = appendArg(a.args, key, "", argsNoValue)
}
// AddNoValue adds only 'key' as argument without the '='.
//
// Multiple values for the same key may be added.