code: def setup(app):
      
      app.setup_extension('nbsphinx')
      app.add_source_suffix('.nblink', 'linked_jupyter_notebook')
      app.add_source_parser(LinkedNotebookParser)
      app.add_config_value('nbsphinx_link_target_root', None, rebuild='env')
  
      return {'version': __version__, 'parallel_read_safe': True}
docs: Initialize Sphinx extension.