code: def tearDown(self):
      self.db.close()
      try:
          os.remove(self.temp_db)
      except:
          pass
  
imports: import logging
  import os
  import tempfile
  import time
  from datetime import datetime, timedelta
  from unittest import TestCase
  import pytest
  from jupyter_client.session import Session
  from ipyparallel import util
  from ipyparallel.controller.dictdb import DictDB
  from ipyparallel.controller.hub import init_record
  from ipyparallel.controller.sqlitedb import SQLiteDB
  from ipyparallel.util import utc
label_desc: Use image node_id 3 for calling the TestSQLiteBackend obj's underlying member method code with example usage: obj.tearDown() without return types