util/gtld.go
func IsInTLDMap(label string) bool {
	label = strings.ToLower(label)
	if _, ok := tldMap[label]; ok {
		return true
	} else {
		return false
	}
}
func IsInTLDMap(label string) bool {
	label = strings.ToLower(label)
	if _, ok := tldMap[label]; ok {
		return true
	} else {
		return false
	}
}
// IsInTLDMap checks that a label is present in the TLD map. It does not
// consider the TLD's validity period and whether the TLD may have been removed,
// only whether it was ever a TLD that was delegated.