private void DoBuyAnimal(Animal animal, int cost)
{
var newStock = new PetShopAnimalViewModel();
newStock.Animal = animal;
newStock.Price = _pricingModel.CalculateInitialSalesPrice(cost);
newStock.SellCommand = new MvxCommand(() => DoSale(newStock));
BankBalance = BankBalance - cost;
Stock.Add(newStock);
}
