class Helper {
    private static $results = [];

    public static askRegistries ($userId) {
        $registries = ['registry1','registry2','registry3'];

        foreach($registries as $registry) {
            self::callRegistry($userId, $registry);
        }

        return self::$results;
    }

    private static callRegistry($userId, $registry) {
        self::$results[] = getData($userId)
    }
}