docs: def get_context_data(self, **kwargs):
          """Tests cookies.
          """
          self.request.session.set_test_cookie()
          if not self.request.session.test_cookie_worked():
              messages.add_message(
                  self.request, messages.ERROR, "Please enable cookies.")
          self.request.session.delete_test_cookie()
          return super().get_context_data(**kwargs)