在学习Django教程时遇到了一个我无法解决的问题。希望你能帮忙。我错过了什么？运行本教程几次，现在双重检查所有工作，代码似乎匹配。
错误：“Not Found：/polls/index.html”

mysite/urls.py：

from django.conf.urls import include, url
from django.contrib import admin

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^polls/', include('polls.urls')),

]

字符串

polls/templates/polls/index.html：

{% if latest_question_list %}
    <ul>
    {% for question in latest_question_list %}
        <li><a href="/polls/{{ question.id }}/">{{ question.question_text }}</a></li>
    {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}

型

民意调查/urls.py：

from django.conf.urls import url

from . import views

urlpatterns = [
    url(r'^$', views.index, name='index'),
    # ex: /polls/5/
    url(r'^(?P<question_id>[0-9]+)/$', views.detail, name='detail'),
    # ex: /polls/5/results/
    url(r'^(?P<question_id>[0-9]+)/results/$', views.results, name='results'),
    # ex: /polls/5/vote/
    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),
]

型

民意调查/views.py：

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.shortcuts import render

# Create your views here.
from django.http import HttpResponse
from .models import Question

def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    template = loader.get_template('polls/index.html')
    context = {
        'latest_question_list': latest_question_list,
    }
    return HttpResponse(template.render(context, request))

def index(request):
    return HttpResponse("Hello, world. You're at the polls index.")

def detail(request, question_id):
    return HttpResponse("You're looking at question %s." % question_id)

def results(request, question_id):
    response = "You're looking at the results of question %s."
    return HttpResponse(response % question_id)

def vote(request, question_id):
    return HttpResponse("You're voting on question %s." % question_id)

型