code: def render_fn_2():
      """Do nothing."""
  
file_path: pytorch-lightning/tests/tests_app/frontend/panel/test_panel_serve_render_fn.py
imports: import inspect
  import os
  from unittest import mock
  import pytest
  from lightning.app.frontend.panel.app_state_watcher import AppStateWatcher
  from lightning.app.frontend.panel.panel_serve_render_fn import _get_render_fn, _get_render_fn_from_environment
  from lightning_utilities.core.imports import RequirementCache
label_desc: Use image node_id 6 for calling a global function with example usage: render_fn_2() without return types