code: def tearDownClass(cls):
      cls.sc.stop()
      if cls.old_pin_thread is not None:
          os.environ["PYSPARK_PIN_THREAD"] = cls.old_pin_thread
      else:
          del os.environ["PYSPARK_PIN_THREAD"]
  
file_path: spark/python/pyspark/tests/test_pin_thread.py
imports: import os
  import time
  import threading
  import unittest
  from pyspark import SparkContext, SparkConf, InheritableThread
label_desc: Use image node_id 2 for calling the PinThreadTests obj's underlying member method code with example usage: obj.tearDownClass(cls) without return types