code: def get_process_index(self, external_address: str):
      for process_index, conf in self._conf["pools"].items():
          if external_address in conf["external_address"]:
              return process_index
      raise ValueError(
          f"Cannot get process_index for {external_address}"
      )
  
file_path: mars/mars/oscar/backends/config.py
imports: from typing import Union, List, Dict, Any
label_desc: Use image node_id 7 for calling the ActorPoolConfig obj's underlying member method code with example usage: obj.get_process_index(external_address) and returns: process_index