text: from django.shortcuts import HttpResponse, render, get_object_or_404
  from .models import Question, Choice
  from django.http import Http404, HttpResponseRedirect
  from django.urls import reverse
  
  
  def index(request):
      latest_question_list = Question.objects.order_by('-pub_date')[:5]
      context = {
          'latest_question_list': latest_question_list,
      }
      return render(request, 'polls/index.html', context)
  
  
  def detail(request, question_id):
      # try:
      #     question = Question.objects.get(pk=question_id)
      # except Question.DoesNotExist:
      #     raise Http404("Question does not exists.")
      question = get_object_or_404(Question, pk=question_id)
      context = {
          'question': question,
      }
      return render(request, 'polls/detail.html', context)
  
  
  def results(request, question_id):
      question = get_object_or_404(Question, pk=question_id)
      return render(request, 'polls/results.html', {'question': question})
  
  
  def vote(request, question_id):
      question = get_object_or_404(Question, pk=question_id)
      try:
          selected_choice = question.choice_set.get(pk=request.POST['choice'])
      except (KeyError, Choice.DoesNotExist):
          return render(
              request,
              'polls/detail.html',
              {
                  'question': question,
                  'error_message': "You didn't select a choice.",
              }
          )
      else:
          selected_choice.votes += 1
          selected_choice.save()
          return HttpResponseRedirect(reverse('polls:results', args=(question_id,)))
  