code: def tearDown(self):
      policy = asyncio.get_event_loop_policy()
      if policy.loop is not None:
          self.assertTrue(policy.loop.is_closed())
          self.assertTrue(policy.loop.shutdown_ag_run)
  
      asyncio.set_event_loop_policy(None)
      super().tearDown()
  
imports: import _thread
  import asyncio
  import contextvars
  import re
  import signal
  import sys
  import threading
  import unittest
  from test.test_asyncio import utils
  from unittest import mock
  from unittest.mock import patch
label_desc: Use image node_id 3 for calling the BaseTest obj's underlying member method code with example usage: obj.tearDown() without return types