docs: def main(args=None):
      """Main function for usage of psyplot from the command line
  
      This function creates a parser that parses command lines to the
      :func:`make_plot` functions or (if the ``psyplot_gui`` module is
      present, to the :func:`psyplot_gui.start_app` function)
  
      Returns
      -------
      psyplot.parser.FuncArgParser
          The parser that has been used from the command line"""
      try:
          from psyplot_gui import get_parser as _get_parser
      except ImportError:
          logger.debug('Failed to import gui', exc_info=True)
          parser = get_parser(create=False)
          parser.update_arg('output', required=True)
          parser.create_arguments()
          parser.parse2func(args)
      else:
          parser = _get_parser(create=False)
          parser.create_arguments()
          parser.parse_known2func(args)