code: def __post_init__(self):
      if isinstance(self.backend, str):
          self.backend = BackendType(self.backend).get_backend(
              self.entrypoint
          )
  
      if self.app is not None:
          LightningFlow._attach_backend(self.app.root, self.backend)
  
imports: import multiprocessing
  import os
  import sys
  from dataclasses import dataclass, field
  from pathlib import Path
  from threading import Thread
  from typing import TYPE_CHECKING, Any, Dict, List, Optional, Type, Union
  from lightning.app.core import LightningApp, LightningFlow
  from lightning.app.core.constants import APP_SERVER_HOST, APP_SERVER_PORT
  from lightning.app.runners.backends import Backend, BackendType
  from lightning.app.utilities.app_helpers import Logger
  from lightning.app.utilities.enum import AppStage, CacheCallsKeys, WorkStageStatus, make_status
  from lightning.app.utilities.load_app import load_app_from_file
  from lightning.app.utilities.proxies import WorkRunner
label_desc: Use image node_id 1 for calling the Runtime obj's underlying member method code with example usage: obj.__post_init__() without return types