public Money MakePurchase(IReadOnlyList <IPurchaseItem> products)
{
//find a better way to do this here...
var currency = products.First().Product.Cost.Currency;
var po = new PurchaseOrder(currency, discountCalculator);
foreach (var item in products)
{
po.AddProduct(item);
}
var total = po.TotalCost;
return(total);
}
