code: func NameIsDNSLabel(name string, prefix bool) (bool, string) {
  	if prefix {
  		name = maskTrailingDash(name)
  	}
  	if validation.IsDNS1123Label(name) {
  		return true, ""
  	}
  	return false, DNS1123LabelErrorMsg
  }
docs: // NameIsDNSLabel is a ValidateNameFunc for names that must be a DNS 1123 label.