ok = true

	featureSet := set(features)
	exceptionSet := set(exception)

	sort.Strings(features)
	sort.Strings(required)

	take := func(sl *[]string) string {
		s := (*sl)[0]
		*sl = (*sl)[1:]
		return s
	}

	for len(features) > 0 || len(required) > 0 {
		switch {
		case len(features) == 0 || (len(required) > 0 && required[0] < features[0]):