code: def test_bokeh_custom(self, cat) -> None:
      r = warnings.formatwarning("message", cat, "line", "lineno")
      assert r == f"{cat.__name__}: message\n"
  
file_path: bokeh/tests/unit/bokeh/test___init__.py
imports: from __future__ import annotations
  import pytest
  import re
  import warnings
  from bokeh.util.warnings import BokehDeprecationWarning, BokehUserWarning
  from tests.support.util.api import verify_all
  from tests.support.util.types import Capture
  import bokeh
label_desc: Use image node_id 1 for calling the TestWarnings obj's underlying member method code with example usage: obj.test_bokeh_custom(cat) without return types