code: def test_append_stdout():
      widget = widget_output.Output()
  
      # Try appending a message to stdout.
      widget.append_stdout("snakes!")
      expected = (_make_stream_output("snakes!", "stdout"),)
      assert widget.outputs == expected, repr(widget.outputs)
  
      # Try appending a second message.
      widget.append_stdout("more snakes!")
      expected += (_make_stream_output("more snakes!", "stdout"),)
      assert widget.outputs == expected, repr(widget.outputs)
  
file_path: catboost/contrib/python/ipywidgets/py3/ipywidgets/widgets/tests/test_widget_output.py
imports: import sys
  from unittest import TestCase
  from contextlib import contextmanager
  from IPython.display import Markdown, Image
  from ipywidgets import widget_output
label_desc: Use image node_id 2 for calling a global function with example usage: test_append_stdout() without return types