def add(request, product_key):
postdata = request.POST.copy()
quantity = int(postdata.get('quantity', 1))
product = Product.get(product_key)
item = CartItem.all().filter('product = ',
product).filter('cart_id = ',
get_cart_id(request)).get()
if not item:
item = CartItem()
item.product = product
item.quantity = quantity
item.cart_id = get_cart_id(request)
item.put()
else:
item.quantity = item.quantity + quantity
item.put()
