final protected static function get_context_structure() {
        return array(
            'contextid' => new external_value(PARAM_INT, 'The context id', VALUE_OPTIONAL),
            'contextlevel' => new external_value(PARAM_ALPHA, 'The context level', VALUE_OPTIONAL),
            'instanceid' => new external_value(PARAM_INT, 'The Instance id', VALUE_OPTIONAL),
        );
    }