public static function update_notes_parameters() {
        return new external_function_parameters(
            array(
                'notes' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'id' => new external_value(PARAM_INT, 'id of the note'),
                            'publishstate' => new external_value(PARAM_ALPHA, '\'personal\', \'course\' or \'site\''),
                            'text' => new external_value(PARAM_RAW, 'the text of the message - text or HTML'),
                            'format' => new external_format_value('text', VALUE_DEFAULT),
                        )
                    ), "Array of Notes", VALUE_DEFAULT, array()
                )
            )
        );
    }