code: def test__update_notebook_url_from_env_4(mock_warning) -> None:
      def proxy_url_func(int):
          return "https://some-url.com"
  
      rval = binb._update_notebook_url_from_env(proxy_url_func)
      assert mock_warning.called
      assert rval == binb._remote_jupyter_proxy_url
  
imports: from __future__ import annotations
  import pytest
  import json
  import os
  from typing import Any
  from unittest.mock import MagicMock, PropertyMock, patch
  from bokeh.document.document import Document
  from bokeh.io.notebook import log
  from bokeh.io.state import State
  import bokeh.io.notebook
label_desc: Use image node_id 10 for calling a global function with example usage: test__update_notebook_url_from_env_4(mock_warning) and returns: str