old_contents: from rest_framework import routers
  from .views import SubjectViewSet
  
  router = routers.DefaultRouter()
  router.register(r'subjects', SubjectViewSet)
  
new_contents: from rest_framework import routers
  from .views import (SubjectViewSet, SubjectDetailViewSet)
  
  router = routers.SimpleRouter()
  router.register(r'qiprofile/(?P<collection>\w+)/subjects', SubjectViewSet)
  router.register(r'qiprofile/subject-detail', SubjectDetailViewSet)
  
subject: Add qiprofile prefix.