public static function submit_answers_parameters() {
        return new external_function_parameters(
            array(
                'surveyid' => new external_value(PARAM_INT, 'Survey id'),
                'answers' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'key' => new external_value(PARAM_RAW, 'Answer key'),
                            'value' => new external_value(PARAM_RAW, 'Answer value')
                        )
                    )
                ),
            )
        );
    }