code: def __init__(self) -> None:
      self.http_session = aiohttp.ClientSession()
      self.prometheus_host = os.environ.get(
          PROMETHEUS_HOST_ENV_VAR, DEFAULT_PROMETHEUS_HOST
      )
  
file_path: ray/release/ray_release/command_runner/_prometheus_metrics.py
imports: import asyncio
  import aiohttp
  import os
  import time
  import traceback
  from urllib.parse import quote
  from typing import Optional
  import logging
  import json
  import argparse
label_desc: Use image node_id 1 to create a new PrometheusClient object  with example: obj = PrometheusClient()