code: def test_call_interact_on_trait_changed_none_return(clear_display):
      def foo(a="default"):
          pass
  
      with patch.object(interaction, "display", record_display):
          ifoo = interact(foo)
      assert len(displayed) == 1
      w = displayed[0].children[0]
      check_widget(
          w,
          cls=widgets.Text,
          value="default",
      )
      with patch.object(interaction, "display", record_display):
          w.value = "called"
      assert len(displayed) == 1
  
imports: from __future__ import print_function
  import os
  from collections import OrderedDict
  import pytest
  import ipywidgets
  from traitlets import TraitError
  from ipywidgets import interact, interact_manual, interactive, interaction, Output
  from ipython_genutils.py3compat import annotate
  from .utils import setup, teardown
label_desc: Use image node_id 28 for calling a global function with example usage: test_call_interact_on_trait_changed_none_return(clear_display) without return types