rangeSpendDeferredPromo method
Implementation
int rangeSpendDeferredPromo(DateTime start, DateTime end) =>
where((t) => t.status == true)
.where((t) => t.date.isAfter(start))
.where((t) => t.date.isBefore(end))
.where((t) => t.paymentType == PaymentType.nope)
.where((t) => t.ticketType == TicketType.spendDeferred)
.fold(0.0, (num prev, element) => prev + (element.totalCostPromoVal))
.round();