/// <summary>
/// Scan method, takes product code as input parrameter
/// and add them to cart in case if product code available in pricing.
/// </summary>
/// <exception cref="KeyNotFoundException">In case if product code is missing in pricing</exception>
public void Scan(string productCode)
{
if (!prices.ContainsKey(productCode))
{
throw new KeyNotFoundException($"You are trying to scan product {productCode} missing in the pricing");
}
cart.AddProductItem(productCode);
}
