code: def _validate_root_flow(flow: "LightningFlow") -> None:
      from lightning.app.core.flow import LightningFlow
  
      if not is_overridden("run", instance=flow, parent=LightningFlow):
          raise TypeError(
              "The root flow passed to `LightningApp` does not override the `run()` method. This is required. Please"
              f" implement `run()` in your `{flow.__class__.__name__}` class."
          )
  
imports: import os
  from contextlib import contextmanager
  from typing import TYPE_CHECKING, Any, Dict, Generator, Optional
  from deepdiff.helper import NotPresent
  from lightning_utilities.core.apply_func import apply_to_collection
  from lightning.app.utilities.app_helpers import is_overridden
  from lightning.app.utilities.enum import ComponentContext
  from lightning.app.utilities.packaging.cloud_compute import CloudCompute
  from lightning.app.utilities.tree import breadth_first
label_desc: Use image node_id 13 for calling a global function with example usage: _validate_root_flow(flow) without return types