old_contents: from django.conf.urls import url, include
  from django.contrib import admin
  
  urlpatterns = [
      url(r'^api/', include('api.urls')),
      url(r'^admin/', admin.site.urls),
  ]
  
new_contents: from django.conf.urls.i18n import i18n_patterns
  from django.conf.urls import url, include
  from django.contrib import admin
  
  # URLs that shouldn't be translated.
  urlpatterns = [
      url(r'^api/', include('api.urls')),
  ]
  
  # URLs that should be translated.
  urlpatterns += i18n_patterns(
      url(r'^admin/', admin.site.urls),
  )
  
subject: Add i18n_patterns. (#75)