old_contents: from django.conf.urls import url
  
  from .views import SignInView
  
  
  urlpatterns = [
      url(
          regex=r'^sign-in/$',
          view=SignInView.as_view(),
          name='sign_in'
      ),
  ]
  
new_contents: from django.conf.urls import url
  from django.contrib.auth.views import login, logout, logout_then_login, 
  from .views import SignInView
  
  
  urlpatterns = [
  
      # Authentication
      # ==============
      url(
          regex=r'^login/$',
          view=login,
          name='login'
      ),
  
      url(
          regex=r'^logout/$',
          view=logout,
          name='logout'
      ),
  
      url(
          regex=r'^logout-then-login/$',
          view=logout_then_login,
          name='logout_then_login'
      ),
  
  ]
  
subject: Delete custom urls and add urls for built in auth views