public static function request_password_reset_parameters() {
        return new external_function_parameters(
            array(
                'username' => new external_value(core_user::get_property_type('username'), 'User name', VALUE_DEFAULT, ''),
                'email' => new external_value(core_user::get_property_type('email'), 'User email', VALUE_DEFAULT, ''),
            )
        );
    }