old_contents: from django.conf.urls import include, url
  from django.contrib import admin
  
  from lists.views import home_page
  from core.views import custom_server_error
  
  # error pages
  # handler400 = 'core.views.custom_bad_request'
  # handler403 = 'core.views.custom_permission_denied'
  # handler404 = 'core.views.custom_page_not_found'
  # handler500 = 'core.views.custom_server_error'
  # handler502 = 'core.views.custom_bad_gateway'
  
  urlpatterns = [
  
      url(r'^$', home_page, name='home'),
  
      url(r'^lists/', include('lists.urls')),
  
      url(r'^admin/', include(admin.site.urls)),
  
      # url(r'^(\d)/$', custom_server_error, name='custom-server-error'),
  ]
  
new_contents: from django.conf.urls import include, url
  from django.contrib import admin
  
  from lists.views import home_page
  # from core.views import custom_server_error
  
  # error pages
  # handler400 = 'core.views.custom_bad_request'
  # handler403 = 'core.views.custom_permission_denied'
  # handler404 = 'core.views.custom_page_not_found'
  # handler500 = 'core.views.custom_server_error'
  # handler502 = 'core.views.custom_bad_gateway'
  
  urlpatterns = [
  
      url(r'^$', home_page, name='home'),
  
      url(r'^lists/', include('lists.urls')),
  
      url(r'^admin/', include(admin.site.urls)),
  
      # url(r'^(\d)/$', custom_server_error, name='custom-server-error'),
  ]
  
subject: Remove customer server error view temporarily.