public BoughtItem ForNewItem(BoughtItem boughtItem, int quantity, int itemId)
{
var boughtItems = new BoughtItem()
{
ItemId = itemId,
Quantity = quantity
};
return(boughtItems);
}
public BoughtItem ForExistingItem(BoughtItem boughtItem, int quantity)
{
boughtItem.Quantity += quantity;
return(boughtItem);
}
