copyWith method
Создает экземпляр с заданными параметрами
Implementation
@override
RefundRequest copyWith({
int? amount,
String? orderId,
Map<String, dynamic>? jsonParams,
}) {
return RefundRequest(
amount: amount ?? this.amount,
orderId: orderId ?? this.orderId,
jsonParams: jsonParams ?? this.jsonParams,
);
}