Check anonymous in cource detail view

apps/course/views.py

@@ -190,6 +190,7 @@ class CourseView(DetailView):
 
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
+        if not self.request.user.is_anonymous:
             context['next'] = self.request.GET.get('next', None)
             context['paid'] = self.object.payments.filter(
                 user=self.request.user,