code: def teardown_class(cls):
      time.sleep(10)  # Wait all background spark job canceled.
      cls.spark.stop()
      os.environ.pop("SPARK_WORKER_CORES")
  
file_path: ray/python/ray/tests/spark/test_databricks_hook.py
imports: import sys
  import pytest
  import os
  import time
  import ray
  from pyspark.sql import SparkSession
  from ray.util.spark import setup_ray_cluster
  import ray.util.spark.databricks_hook
label_desc: Use image node_id 2 for calling the TestDatabricksHook obj's underlying member method code with example usage: obj.teardown_class(cls) without return types