import 'package:formz/formz.dart'; enum TransactionAccountValidationError { empty('Account empty'), invalid('Account invalid'); final String message; const TransactionAccountValidationError(this.message); } class TransactionAccount extends FormzInput { const TransactionAccount.pure() : super.pure(''); const TransactionAccount.dirty([super.value = '']) : super.dirty(); @override TransactionAccountValidationError? validator(String value) { return value.isEmpty ? TransactionAccountValidationError.empty : null; } }