code: def configure_layout(self):
      frontend = StreamlitFrontend(render_fn=_render_streamlit_fn)
      frontend.start_server = Mock()
      frontend.stop_server = Mock()
      return frontend
  
imports: from re import escape
  from unittest import mock
  from unittest.mock import Mock
  import pytest
  from lightning.app import LightningApp, LightningFlow
  from lightning.app.frontend.stream_lit import StreamlitFrontend
  from lightning.app.frontend.web import StaticWebFrontend
  from lightning.app.runners import MultiProcessRuntime
  from lightning.app.testing.helpers import EmptyFlow
  from lightning.app.utilities.imports import _IS_WINDOWS
label_desc: Use image node_id 3 for calling the StreamlitFrontendFlow obj's underlying member method code with example usage: obj.configure_layout() and returns: frontend