/// <summary>
        /// Add product to the shop
        /// </summary>
        /// <param name="product">product to be added </param>
        /// <exception cref="ArgumentNullException">Product must not be null</exception>
        public void AddProductToShop(ProductEntity product)
        {
            if (ReferenceEquals(product, null))
            {
                throw new ArgumentNullException($"{nameof(product)} must not be null");
            }

            productService.Create(product.ToDalProduct());
            productService.Commit();
        }
        /// <summary>
        /// add purchase to the shop
        /// </summary>
        /// <param name="purch">purchase to be added</param>
        public void RegisterPurchase(PurchaseEntity purch)
        {
            if (ReferenceEquals(purch, null))
            {
                throw new ArgumentNullException($"{nameof(purch)} must not be null");
            }

            purchaseService.Create(purch.ToDallPurchase());
            purchaseService.Commit();
        }