code: def vote_count(self):
          
          return Vote.objects.filter(
              content_type=ContentType.objects.get(app_label='poll', model='polloption'),
              object_id__in=[o.id for o in self.polloption_set.all()]
          ).aggregate(Sum('vote'))['vote__sum'] or 0
docs: Returns the total number of votes cast across all the
          poll's options.