old_contents: from django.conf.urls import patterns, include, url
  
  from views import PostListView, PostDetailView
  
  
  urlpatterns = patterns('',
      url(r'^$', PostListView.as_view(), name='list'),
      url(r'^(?P<pk>[\d]+)/$', PostDetailView.as_view(), name='detail'),
      url(r'^(?P<slug>[-\w]+)/$', PostDetailView.as_view(), name='detail-by-slug'),
  )
  
new_contents: from django.conf.urls import patterns, url
  
  from views import PostListView, PostDetailView
  
  
  urlpatterns = patterns('',
      url(r'^$', PostListView.as_view(), name='list'),
      url(r'^(?P<pk>[\d]+)/$', PostDetailView.as_view(), name='detail'),
      url(r'^(?P<slug>[-\w]+)/$', PostDetailView.as_view(), name='detail-by-slug'),
  )
  
subject: remove unused import from urls.py