code: def test_bad_markdown_metadata():
      """Test exception raised if markdown metadata cannot be parsed."""
      with pytest.raises(MystMetadataParsingError):
          myst_to_notebook(
              dedent(
                  """\
              +++ {{a
              """
              )
          )
  
imports: import json
  import unittest.mock
  from textwrap import dedent
  import pytest
  from nbformat.v4.nbbase import new_notebook
  from tornado.web import HTTPError
  import jupytext
  from jupytext.cli import jupytext
  from jupytext.compare import compare
  from jupytext.formats import JupytextFormatError, get_format_implementation, guess_format
  from jupytext.myst import CODE_DIRECTIVE, MystMetadataParsingError, matches_mystnb, myst_extensions, myst_to_notebook
label_desc: Use image node_id 3 for calling a global function with example usage: test_bad_markdown_metadata() without return types