Kooboo.Commerce.Carts.ShoppingCartService.ChangeItemQuantity C# (CSharp) Method

        public void ChangeItemQuantity(ShoppingCart cart, ShoppingCartItem item, int newQuantity)
        {
            Require.NotNull(cart, "cart");
            Require.NotNull(item, "item");
            Require.That(newQuantity > 0, "newQuantity", "Quantity should be greater than zero.");

            if (item.Quantity != newQuantity)
            {
                var oldQuantity = item.Quantity;
                item.Quantity = newQuantity;

                _repository.Database.SaveChanges();

                Event.Raise(new CartItemQuantityChanged(cart, item, oldQuantity), _instance);
            }
        }

 public void ChangeItemQuantity(int cartId, int itemId, int newQuantity)
 {
     var service = new Core.ShoppingCartService(_context.Instance);
     var cart = service.Find(cartId);
     var item = cart.Items.FirstOrDefault(i => i.Id == itemId);
     if (item != null)
     {
         _context.Database.Transactional(() =>
         {
             service.ChangeItemQuantity(cart, item, newQuantity);
         });
     }
 }