code: def session(self):
      return self._session
  
imports: import logging
  import time
  import warnings
  import requests
  from ...session import new_session
  from .config import MarsSchedulerSpecConfig, MarsWorkerSpecConfig, MarsWebSpecConfig, MarsJobConfig
label_desc: Use image node_id 4 for calling the KubeDLClusterClient obj's underlying member method code with example usage: obj.session() and returns: self