code: def tear_down(self):
      # restore default file availability wait timeout
      spark_dataset_converter._FILE_AVAILABILITY_WAIT_TIMEOUT_SECS = 30
      self.spark.stop()
  
imports: import logging
  import os
  import pickle
  import tempfile
  from base64 import b64encode, b64decode
  from collections import namedtuple
  import pytest
  import six
  from petastorm.spark import spark_dataset_converter, SparkDatasetConverter
  from petastorm.tests.test_common import create_test_dataset, create_test_scalar_dataset, create_many_columns_non_petastorm_dataset
  from pyspark.sql import SparkSession
label_desc: Use image node_id 2 for calling the SparkTestContext obj's underlying member method code with example usage: obj.tear_down() without return types