Code debt example

GetTenderAmount.cs

// Bad version
protected DollarCents Calculate() {
    var x = Events.OfType<CardSaleAttached>().Select(e => e.Sale)
        .Aggregate(DollarCents.Zero, (a, b) => a + b.SecuredMoney());
    var y = Events.OfType<FolioPaymentReceived>()
        .Aggregate(DollarCents.Zero, (a, b) => a + b.Amount);
    return x + y;
}

// Good version
protected DollarCents GetCurrentIrrevocableTenderAmount() {
    var cardTenders = Events.OfType<CardSaleAttached>().Select(e => e.Sale)
        .Aggregate(DollarCents.Zero, (total, sale) => total + sale.SecuredMoney());
    var cashAndCheckTenders = Events.OfType<FolioPaymentReceived>()
        .Aggregate(DollarCents.Zero, (total, payment) => total + payment.Amount);
    return cardTenders + cashAndCheckTenders;
}