stack_wallet/lib/services/buy/buy_response.dart

enum BuyExceptionType {
  generic,
  serializeResponseError,
  cryptoAmountOutOfRange,
}

class BuyException implements Exception {
  String errorMessage;
  BuyExceptionType type;
  BuyException(this.errorMessage, this.type);

  @override
  String toString() {
    return errorMessage;
  }
}

class BuyResponse<T> {
  final T? value;
  final BuyException? exception;

  BuyResponse({this.value, this.exception});

  @override
  String toString() {
    return "{error: $exception, value: $value}";
  }
}