old_contents: from django.conf.urls import include, url
  from testing import views
  
  urlpatterns = [
      url(r'^$', views.IndexViews.as_view(), name='index'),
  
      url(r'^success/', views.SuccessViews.as_view(), name='success'),
  
      url(r'^sendmessage/', views.sendmessage, name='sendmessage'),
  
      url(r'^ios/', views.IOSViews.as_view(), name='ios'),
  
      url(r'^android/', views.ANDROIDViews.as_view(), name='android'),
  ]
new_contents: from django.conf.urls import include, url
  from testing import views
  
  urlpatterns = [
      url(r'^$', views.IndexViews.as_view(), name='index'),
  
      url(r'^success/$', views.SuccessViews.as_view(), name='success'),
  
      url(r'^sendmessage/$', views.sendmessage, name='sendmessage'),
  
      url(r'^ios/$', views.IOSViews.as_view(), name='ios'),
  
      url(r'^android/$', views.ANDROIDViews.as_view(), name='android'),
  ]
  
subject: Update urls.py