title: AttributeError at /cart type object 'Cart' has no attribute 'model'
body: <pre><code>class Cart(View):
      def get(self , request):
          customer_id = request.session['customer']
          cart = get_object_or_404(Cart, customer_id= customer_id)
          return render(request , 'cart.html')
  </code></pre>
  <p>I am not able to get the cart object</p>