code: def clear(
      self, context: AuthedServiceContext
  ) -> Union[SyftError, SyftSuccess]:
      result = self.stash.delete_all_for_verify_key(
          credentials=context.credentials,
          verify_key=context.credentials,
      )
      if result.is_ok():
          return SyftSuccess(message="All notifications cleared !!")
      return SyftError(message=str(result.err()))
  
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 12 for calling the NotificationService obj's underlying member method code with example usage: obj.clear(context) and returns: SyftError, SyftSuccess