old_contents: # coding: utf-8
  from django.contrib.auth.backends import ModelBackend
  
  from .utils import get_user_model
  
  
  class DartCMSAuthBackend(ModelBackend):
      default_user_model = 'auth.User'
  
      @property
      def user_model(self):
          return get_user_model()
  
      def authenticate(self, username=None, password=None, **kwargs):
          try:
              user = self.user_model.objects.get(username=username, is_active=True, is_staff=True)
              if user.check_password(password):
                  return user
          except self.user_model.DoesNotExist:
              return None
  
      def get_user(self, user_id):
          try:
              return self.user_model.objects.get(pk=user_id)
          except self.user_model.DoesNotExist:
              return None
  
new_contents: # coding: utf-8
  from django.contrib.auth.backends import ModelBackend
  
  from .utils import get_user_model
  
  
  class DartCMSAuthBackend(ModelBackend):
      @property
      def user_model(self):
          return get_user_model()
  
      def authenticate(self, username=None, password=None, **kwargs):
          try:
              user = self.user_model.objects.get(username=username, is_active=True, is_staff=True)
              if user.check_password(password):
                  return user
          except self.user_model.DoesNotExist:
              return None
  
      def get_user(self, user_id):
          try:
              return self.user_model.objects.get(pk=user_id)
          except self.user_model.DoesNotExist:
              return None
  
subject: Remove useless prop