old_contents: from django.conf.urls import patterns, include, url
  
  from slackin.views import SlackinInviteView
  
  urlpatterns = patterns(
      '',
      url(r'^$', SlackinInviteView.as_view(), name='slackin_invite'),
  )
  
new_contents: from django.conf.urls import patterns, url
  
  from slackin.views import SlackinInviteView
  
  urlpatterns = patterns(
      '',
      url(r'^$', SlackinInviteView.as_view(), name='slackin_invite'),
  )
  
subject: remove unused import