code: def _get_render_fn():
      render_fn_name = os.environ["LIGHTNING_RENDER_FUNCTION"]
      render_fn_module_file = os.environ["LIGHTNING_RENDER_MODULE_FILE"]
      render_fn = _get_render_fn_from_environment(
          render_fn_name, render_fn_module_file
      )
      if inspect.signature(render_fn).parameters:
  
          def _render_fn_wrapper():
              app = AppStateWatcher()
              return render_fn(app)
  
          return _render_fn_wrapper
      return render_fn
  
file_path: pytorch-lightning/src/lightning/app/frontend/panel/panel_serve_render_fn.py
imports: import inspect
  import os
  import pydoc
  from typing import Callable
  from lightning.app.frontend.panel.app_state_watcher import AppStateWatcher
label_desc: Use image node_id 2 for calling a global function with example usage: _get_render_fn() and returns: render_fn, _render_fn_wrapper, render_fn