code: def linked_object():
      return LinkedObject(
          node_uid=UID(),
          service_type=NotificationService,
          object_type=Notification,
          object_uid=UID(),
      )
  
file_path: PySyft/packages/syft/tests/syft/notifications/fixtures.py
imports: import pytest
  from syft.node.credentials import SyftSigningKey
  from syft.node.credentials import SyftVerifyKey
  from syft.node.worker import Worker
  from syft.service.context import AuthedServiceContext
  from syft.service.notification.notification_service import NotificationService
  from syft.service.notification.notification_stash import NotificationStash
  from syft.service.notification.notifications import CreateNotification
  from syft.service.notification.notifications import Notification
  from syft.service.user.user import User
  from syft.store.linked_obj import LinkedObject
  from syft.types.datetime import DateTime
  from syft.types.uid import UID
label_desc: Use image node_id 4 for calling a global function with example usage: linked_object() and returns: LinkedObject