services/transaction_service library
Functions
- 
  checkCoupon(
String? userId, String amount, String? couponCode, Config config) → Future< ValidateCouponModel>  - 
  fetchTransactionProfile(
String userId, String currency, Config config) → Future< TransactionProfileModel>  - 
  fetchTransactions(
int limit, int offset, String? filter, Config config) → Future< TransactionListModel>