code: def __init__(self, interval_s: int = 1):
      self.dashboard_url = get_address_for_submission_client(None)
      # Ping interval for all endpoints.
      self.interval_s = interval_s
      # endpoint -> a list of latencies
      self.result = defaultdict(list)
  
imports: import asyncio
  import time
  import urllib
  from typing import Dict, Optional, List
  from pprint import pprint
  import requests
  import ray
  import logging
  from collections import defaultdict
  from ray.util.state import list_nodes
  from ray._private.test_utils import fetch_prometheus_metrics
  from ray.util.scheduling_strategies import NodeAffinitySchedulingStrategy
  from pydantic import BaseModel
  from ray.dashboard.consts import DASHBOARD_METRIC_PORT
  from ray.dashboard.utils import get_address_for_submission_client
label_desc: Use image node_id 1 to create a new DashboardTester object  with example: obj = DashboardTester(interval_s)