old_contents: from django.conf.urls import patterns, url
  
  from masquerade.views import mask
  from masquerade.views import unmask
  
  
  urlpatterns = [
      url(r'^mask/$', mask),
      url(r'^unmask/$', unmask),
  ]
  
new_contents: from django.conf.urls import url
  
  from masquerade.views import mask
  from masquerade.views import unmask
  
  
  urlpatterns = [
      url(r'^mask/$', mask),
      url(r'^unmask/$', unmask),
  ]
  
subject: Remove unused import