old_contents: from django.conf.urls import url
  from django.contrib import admin
  
  from core.views import IndexView
  
  urlpatterns = [
      url(
          regex=r'^$',
          view=IndexView.as_view(),
          name='index'
      ),
      url(
          regex=r'^admin/',
          view=admin.site.urls),
  ]
  
new_contents: from django.conf.urls import url
  from django.contrib import admin
  
  from core.views import IndexView
  
  urlpatterns = [
      url(
          regex=r'^$',
          view=IndexView.as_view(),
          name='index'
      ),
      url(
          regex=r'^admin/',
          view=admin.site.urls
      ),
  ]
  
subject: Update base.py