code: def filter_by_obj(
      self, context: AuthedServiceContext, obj_uid: UID
  ) -> Union[Notification, SyftError]:
      notifications = self.stash.get_all(context.credentials)
      if notifications.is_ok():
          for notification in notifications.ok():
              if (
                  notification.linked_obj
                  and notification.linked_obj.object_uid == obj_uid
              ):
                  return notification
      else:
          return SyftError(message="Could not get notifications!!")
  
imports: from typing import List
  from typing import Union
  from ...serde.serializable import serializable
  from ...store.document_store import DocumentStore
  from ...types.uid import UID
  from ...util.telemetry import instrument
  from ..action.action_permissions import ActionObjectREAD
  from ..context import AuthedServiceContext
  from ..response import SyftError
  from ..response import SyftSuccess
  from ..service import AbstractService
  from ..service import SERVICE_TO_TYPES
  from ..service import TYPE_TO_SERVICE
  from ..service import service_method
  from ..user.user_roles import DATA_SCIENTIST_ROLE_LEVEL
  from ..user.user_roles import GUEST_ROLE_LEVEL
  from .notification_stash import NotificationStash
  from .notifications import CreateNotification
  from .notifications import LinkedObject
  from .notifications import Notification
  from .notifications import NotificationStatus
  from .notifications import ReplyNotification
label_desc: Use image node_id 13 for calling the NotificationService obj's underlying member method code with example usage: obj.filter_by_obj(context, obj_uid) and returns: SyftError, notification