code: def get_queryset(self):
          
          forums = self.request.forum_permission_handler.get_readable_forums(
              Forum.objects.all(), self.request.user,
          )
          topics = Topic.objects.filter(forum__in=forums)
          topics_pk = map(lambda t: t.pk, track_handler.get_unread_topics(topics, self.request.user))
          return Topic.approved_objects.filter(pk__in=topics_pk).order_by('-last_post_on')
docs: Returns the list of items for this view.