old_contents: from django.db import models
  from django.db.models.manager import BaseManager
  from .helper import bulk_update
  
  
  class BulkUpdateQuerySet(models.QuerySet):
      def bulk_update(self, objs, update_fields=None, exclude_fields=None):
          self._for_write = True
          bulk_update(objs, update_fields=update_fields,
                      exclude_fields=exclude_fields, using=self.db)
  
  
  class BulkUpdateManager(BaseManager.from_queryset(BulkUpdateQuerySet)):
      pass
  
new_contents: from django.db import models
  from django.db.models.manager import BaseManager
  from .helper import bulk_update
  
  
  class BulkUpdateQuerySet(models.QuerySet):
      def bulk_update(self, objs, update_fields=None, exclude_fields=None, batch_size=None):
          self._for_write = True
          return bulk_update(
              objs, update_fields=update_fields,
              exclude_fields=exclude_fields, using=self.db,
              batch_size=batch_size)
  
  
  class BulkUpdateManager(BaseManager.from_queryset(BulkUpdateQuerySet)):
      pass
  
subject: add batch size