code: def test_default_traits():
      app = JupyterApp()
      for trait_name in app.traits():
          getattr(app, trait_name)
  
imports: from __future__ import annotations
  import asyncio
  import os
  import shutil
  from tempfile import mkdtemp
  from unittest.mock import patch
  import pytest
  from traitlets import Integer
  from jupyter_core.application import JupyterApp, JupyterAsyncApp, NoStart
  from jupyter_core.utils import ensure_event_loop
label_desc: Use image node_id 2 for calling a global function with example usage: test_default_traits() without return types