old_contents: from django.conf.urls import url
  
  from . import views
  
  urlpatterns = [
      url(r'^(?P<slug>[-\w_]+)/$',
          views.PlanDetailView.as_view(), name='plan-detail'),
      url('^export/all/$',
          views.PlanExportView.as_view(), name='plan-export'),
      url('^$',
          views.PlanListView.as_view(), name='plan-list'),
  ]
  
new_contents: from django.conf.urls import url
  
  from . import views
  
  urlpatterns = [
      url(r'^(?P<slug>[-\w_]+)/$',
          views.PlanDetailView.as_view(), name='plan-detail'),
      url('^export/format/xslx/$',
          views.PlanExportView.as_view(), name='plan-export'),
      url('^$',
          views.PlanListView.as_view(), name='plan-list'),
  ]
  
subject: Use format in export url