text: from django.shortcuts import render, get_object_or_404
  from django.http import HttpResponseRedirect, HttpResponse
  from django.core.urlresolvers import reverse
  
  from django.views import generic
  
  from polls.models import Choice, Question
  from django.utils import timezone
  
  
  class IndexView(generic.ListView):
      template_name = 'polls/index.html'
      context_object_name = 'latest_question_list'
  
      def get_queryset(self):
          """Return the last five published questions."""
          return Question.objects.filter(
              pub_date__lte=timezone.now()
          ).order_by('-pub_date')[:5]
  
  class DetailView(generic.DetailView):
      model = Question
      template_name = 'polls/detail.html'
  
      def get_queryset(self):
          """
          Excludes any questions that aren't published yet.
          """
          return Question.objects.filter(pub_date__lte=timezone.now())
  
  
  class ResultsView(generic.DetailView):
      model = Question
      template_name = 'polls/results.html'
  
  def vote(request, question_id):
      p = get_object_or_404(Question, pk=question_id)
      try:
          selected_choice = p.choice_set.get(pk=request.POST['choice'])
      except (KeyError, Choice.DoesNotExist):
          # Redisplay the question voting form.
          return render(request, 'polls/detail.html', {
              'question': p,
              'error_message': "You didn't select a choice.",
          })
      else:
          selected_choice.votes += 1
          selected_choice.save()
          # Always return an HttpResponseRedirect after successfully dealing
          # with POST data. This prevents data from being posted twice if a
          # user hits the Back button.
          return HttpResponseRedirect(reverse('polls:results', args=(p.id,)))