test client in tutorial 5 of django

Question

while doing tutorial 5 of django, in the section Django test client every thing work fine until now but when I write this code in shell from "response = client.get(reverse('polls:index'))" I got some error. I am not understanding what the error is about and so not able to correct it.

Please help how to correct it.

Screen shot of error.

Screen shot of error.

this is mysite/polls/views.py

from django.shortcuts import get_object_or_404, render
from django.http import HttpResponseRedirect, HttpResponse
from django.http import HttpResponseRedirect
from django.urls import reverse
from django.views import generic

from .models import Choice, Question


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.order_by('-pub_date')[:5]


class DetailView(generic.DetailView):
    model = Question
    template_name = 'polls/detail.html'


class ResultsView(generic.DetailView):
    model = Question
    template_name = 'polls/results.html'


"""
     "def vote(request, question_id):
     "   ... # same as above, no changes needed.

    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):
            # Redisplay the question voting form.
            return render(request, 'polls/detail.html', {
                'question': question,
                '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=(question.id,)))
"""
    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):
            # Redisplay the question voting form.
            return render(request, 'polls/detail.html', {
        'question': question,
        '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=(question.id,)))

this is mysite/polls/urls.py

from django.conf.urls import url

from . import views

app_name = 'polls'
urlpatterns = [
    url(r'^$', views.IndexView.as_view(), name='index'),
    url(r'^(?P<pk>[0-9]+)/$', views.DetailView.as_view(), name='detail'),
    url(r'^(?P<pk>[0-9]+)/results/$', views.ResultsView.as_view(), name='results'),
    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),
]