code: def _set_headers(self):
      self.send_response(200)
      self.send_header("Content-type", "application/json")
      self.end_headers()
  
file_path: ray/python/ray/autoscaler/_private/spark/spark_job_server.py
imports: import json
  import logging
  import threading
  from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
  from pathlib import Path
  from pyspark.util import inheritable_thread_target
  from ray.util.spark.cluster_init import _start_ray_worker_nodes
label_desc: Use image node_id 2 for calling the SparkJobServerRequestHandler obj's underlying member method code with example usage: obj._set_headers() without return types