code: def _get_web_cluster_api(self):
      supervisor_web_port = os.environ["MARS_K8S_SUPERVISOR_WEB_PORT"]
      web_url = f"http://{self._service_name}.{self._k8s_namespace}:{supervisor_web_port}"
      api = WebClusterAPI(web_url)
      return api
  
file_path: mars/mars/deploy/kubernetes/core.py
imports: import asyncio
  import logging
  import os
  from typing import AsyncGenerator, Dict, List, Optional, TypeVar
  from ...services.cluster import WebClusterAPI
  from ...services.cluster.backends import register_cluster_backend, AbstractClusterBackend
  from ...services.cluster.core import NodeRole
  from ..utils import wait_all_supervisors_ready, next_in_thread
  from .config import MarsReplicationConfig
label_desc: Use image node_id 4 for calling the K8SClusterBackend obj's underlying member method code with example usage: obj._get_web_cluster_api() and returns: api