title: DoesNotExist at /my-cart/ Product matching query does not exist
body: <p>I am working on a django project. But an error occurs just after creating MyCartView. Please someone help me to resolve this error:</p>
  <p><a href="https://i.stack.imgur.com/CfcrC.png" rel="nofollow noreferrer">Error screenshot 1</a></p>
  <p><a href="https://i.stack.imgur.com/MZ8mw.png" rel="nofollow noreferrer">Error screenshot 2</a></p>
  <p>This is 'urls.py' of 'shop' app inside the project -</p>
  <pre><code>from django.urls import path
  from .views import *
  from . import views
  app_name = 'shop'
  
  urlpatterns = [
      path('', IndexView.as_view(), name='index'),
      path('&lt;slug:slug&gt;/', ProductDetailView.as_view(), name='productdetail'),
      path('add-to-cart/&lt;int:product_id&gt;/',
           AddToCartView.as_view(), name='addtocart'),
      path('my-cart/', MyCartView.as_view(), name='mycart'),
  
  ]
  </code></pre>
  <p>This is 'views.py' -</p>
  <pre><code>class ProductDetailView(TemplateView):
      template_name = 'shop/product_detail.html'
  
      def get_context_data(self, **kwargs):
          context = super().get_context_data(**kwargs)
          url_slug = self.kwargs['slug']
          product = Product.objects.get(slug=url_slug)
          context['product'] = product
          return context
  
  
  class MyCartView(TemplateView):
      template_name = 'shop/mycart.html'
  
  </code></pre>
  <p>This is 'mycart.html' -</p>
  <pre><code>{% extends &quot;shop/base.html&quot; %}
  {% load static %}
  
  {% block body %}
  
  &lt;h1&gt;Items in cart&lt;/h1&gt;
  
  
  {% endblock %}
  </code></pre>