The names and values of options in a group.

        Useful for copying options into Application settings::

            from tornado.options import define, parse_command_line, options

            define('template_path', group='application')
            define('static_path', group='application')

            parse_command_line()

            application = Application(
                handlers, **options.group_dict('application'))

        .. versionadded:: 3.1

def group_dict(self, group: str) -> Dict[str, Any]:
        """The names and values of options in a group.

        Useful for copying options into Application settings::

            from tornado.options import define, parse_command_line, options

            define('template_path', group='application')
            define('static_path', group='application')

            parse_command_line()

            application = Application(
                handlers, **options.group_dict('application'))

        .. versionadded:: 3.1
        """
        return dict(
            (opt.name, opt.value())
            for name, opt in self._options.items()
            if not group or group == opt.group_name
        )