toValidationRule method
Transform the FormValidator into a validation rule
Implementation
List toValidationRule() {
  List listData = [data, rules];
  if (message != null) {
    listData.add(message);
  }
  return listData;
}
Transform the FormValidator into a validation rule
List toValidationRule() {
  List listData = [data, rules];
  if (message != null) {
    listData.add(message);
  }
  return listData;
}