code: def test_custom_policy(self):
      with SettingsContext(
          SETTINGS_FILE_CUSTOM_POLICY, "airflow_local_settings"
      ):
          from airflow import settings
  
          settings.import_local_settings()
  
          task_instance = MagicMock()
          task_instance.owner = "airflow"
          with pytest.raises(AirflowClusterPolicyViolation):
              settings.task_must_have_owners(task_instance)
  
imports: from __future__ import annotations
  import os
  import sys
  import tempfile
  from unittest import mock
  from unittest.mock import MagicMock, call, patch
  import pytest
  from airflow.exceptions import AirflowClusterPolicyViolation, AirflowConfigException
  from tests.test_utils.config import conf_vars
label_desc: Use image node_id 9 for calling the TestLocalSettings obj's underlying member method code with example usage: obj.test_custom_policy() without return types