old_contents: # file: api/urls.py
  
  from django.conf.urls import url
  from rest_framework.urlpatterns import format_suffix_patterns
  
  from api import views
  
  app_name = 'api'
  urlpatterns = [
      url(r'^routers/$', views.RouterList.as_view()),
      url(r'^routers/(?P<pk>[0-9]+)/$', views.RouterDetail.as_view()),
      url(r'^nos/$', views.NetworkOsList.as_view()),
      url(r'^nos/(?P<pk>[0-9]+)/$', views.NetworkOsDetail.as_view()),
      url(r'^interfaces/$', views.InterfaceList.as_view()),
      url(r'^interfaces/(?P<pk>[0-9]+)/$', views.InterfaceDetail.as_view()),
      url(r'^logical_interfaces/$', views.LogicalInterfaceList.as_view()),
      url(r'^logical_interfaces/(?P<pk>[0-9]+)/$', views.LogicalInterfaceDetail.as_view()),
      url(r'^ipv6_address/$', views.Ipv6AddressList.as_view()),
      url(r'^ipv6_address/(?P<pk>[0-9]+)/$', views.Ipv6AddressDetail.as_view()),
      url(r'^ipv4_address/$', views.Ipv4AddressList.as_view()),
      url(r'^ipv4_address/(?P<pk>[0-9]+)/$', views.Ipv4AddressDetail.as_view()),
      url(r'^ipv6_static/$', views.Ipv6StaticList.as_view()),
      url(r'^ipv6_static/(?P<pk>[0-9]+)/$', views.Ipv6StaticDetail.as_view()),
      url(r'^ipv4_static/$', views.Ipv4StaticList.as_view()),
      url(r'^ipv4_static/(?P<pk>[0-9]+)/$', views.Ipv4StaticDetail.as_view()),
      url(r'^aut_num/$', views.AutNumList.as_view()),
      url(r'^aut_num/(?P<pk>[0-9]+)/$', views.AutNumDetail.as_view()),
      url(r'^bgp_neighbor/$', views.NeighborList.as_view()),
      url(r'^bgp_neighbor/(?P<pk>[0-9]+)/$', views.NeighborDetail.as_view()),
  ]
  
  urlpatterns = format_suffix_patterns(urlpatterns)
  
new_contents: # file: api/urls.py
  
  from django.conf.urls import url
  from rest_framework.urlpatterns import format_suffix_patterns
  
  from api import views
  
  app_name = 'api'
  urlpatterns = [
      url(r'^routers/$', views.RouterList.as_view(), name='routers'),
      url(r'^routers/(?P<pk>[0-9]+)/$', views.RouterDetail.as_view(), name='routers_detail'),
      url(r'^nos/$', views.NetworkOsList.as_view(), name='network_os'),
      url(r'^nos/(?P<pk>[0-9]+)/$', views.NetworkOsDetail.as_view(), name='network_os_detail'),
      url(r'^interfaces/$', views.InterfaceList.as_view(), name='interfaces'),
      url(r'^interfaces/(?P<pk>[0-9]+)/$', views.InterfaceDetail.as_view(), name='interfaces_detail'),
      url(r'^logical_interfaces/$', views.LogicalInterfaceList.as_view(), name='logical_interfaces'),
      url(r'^logical_interfaces/(?P<pk>[0-9]+)/$', views.LogicalInterfaceDetail.as_view(), name='logical_interfaces_detail'),
      url(r'^ipv6_address/$', views.Ipv6AddressList.as_view(), name='ipv6_address'),
      url(r'^ipv6_address/(?P<pk>[0-9]+)/$', views.Ipv6AddressDetail.as_view(), name='ipv6_address_detail'),
      url(r'^ipv4_address/$', views.Ipv4AddressList.as_view(), name='ipv4_address'),
      url(r'^ipv4_address/(?P<pk>[0-9]+)/$', views.Ipv4AddressDetail.as_view(), name='ipv4_address_detail'),
      url(r'^ipv6_static/$', views.Ipv6StaticList.as_view(), name='ipv6_static'),
      url(r'^ipv6_static/(?P<pk>[0-9]+)/$', views.Ipv6StaticDetail.as_view(), name='ipv6_static_detail'),
      url(r'^ipv4_static/$', views.Ipv4StaticList.as_view(), name='ipv4_static'),
      url(r'^ipv4_static/(?P<pk>[0-9]+)/$', views.Ipv4StaticDetail.as_view(), name='ipv4_static_detail'),
      url(r'^aut_num/$', views.AutNumList.as_view(), name='aut_num'),
      url(r'^aut_num/(?P<pk>[0-9]+)/$', views.AutNumDetail.as_view(), name='aut_num_detail'),
      url(r'^bgp_neighbor/$', views.NeighborList.as_view(), name='bgp_neigbor'),
      url(r'^bgp_neighbor/(?P<pk>[0-9]+)/$', views.NeighborDetail.as_view(), name='bgp_neighbor_detail'),
  ]
  
  urlpatterns = format_suffix_patterns(urlpatterns)
  
subject: Add url names in api/urls.py