old_contents: from django.db import models
  from .helper import bulk_update
  
  
  class BulkUpdateManager(models.Manager):
      def bulk_update(self, objs, update_fields=None, exclude_fields=None):
          bulk_update(objs, update_fields=update_fields,
                      exclude_fields=exclude_fields, using=self.db)
  
new_contents: from django.db import models
  from .helper import bulk_update
  
  
  class BulkUpdateManager(models.Manager):
      def bulk_update(self, objs, update_fields=None, exclude_fields=None):
          return bulk_update(
              objs, update_fields=update_fields,
              exclude_fields=exclude_fields, using=self.db)
  
subject: add return value to the manager as well