old_contents: from django.conf.urls import include, url
  
  
  urlpatterns = [
      url(r'^calculator-demo/?$', 'grade_conversion_calculator.views.demo'),
  ]
  
new_contents: from django.conf.urls import url
  from grade_conversion_calculator.views import demo
  
  
  urlpatterns = [
      url(r'^calculator-demo/?$', demo, name='calculator_demo'),
  ]
  
subject: update urls to include view callables