old_contents: from backend.api.views import (
      CaseViewSet,
      CandidateViewSet,
      NoduleViewSet,
      ImageSeriesViewSet,
      ImageSrcApiView 
      candidate_mark,
      candidate_dismiss,
  )
  from django.conf.urls import (
      include,
      url
  )
  from rest_framework import routers
  
  router = routers.DefaultRouter()
  router.register(r'cases', CaseViewSet)
  router.register(r'candidates', CandidateViewSet)
  router.register(r'nodules', NoduleViewSet)
  router.register(r'images', ImageSeriesViewSet)
  
  urlpatterns = [
      url(r'^', include(router.urls)),
      url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework')),
      url(r'^image_src/$', ImageSrcApiView.as_view()),
      url(r'^candidates/(?P<candidate_id>\d+)/dismiss$', candidate_dismiss, name='candidate-dismiss'),
      url(r'^candidates/(?P<candidate_id>\d+)/mark$', candidate_mark, name='candidate-mark'),
  ]
  
new_contents: from backend.api.views import (
      CaseViewSet,
      CandidateViewSet,
      NoduleViewSet,
      ImageSeriesViewSet,
      ImageSrcApiView,
      candidate_mark,
      candidate_dismiss,
  )
  from django.conf.urls import (
      include,
      url
  )
  from rest_framework import routers
  
  router = routers.DefaultRouter()
  router.register(r'cases', CaseViewSet)
  router.register(r'candidates', CandidateViewSet)
  router.register(r'nodules', NoduleViewSet)
  router.register(r'images', ImageSeriesViewSet)
  
  urlpatterns = [
      url(r'^', include(router.urls)),
      url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework')),
      url(r'^image_src/$', ImageSrcApiView.as_view()),
      url(r'^candidates/(?P<candidate_id>\d+)/dismiss$', candidate_dismiss, name='candidate-dismiss'),
      url(r'^candidates/(?P<candidate_id>\d+)/mark$', candidate_mark, name='candidate-mark'),
  ]
  
subject: Fix typo