protected static function prepareTypes($config)
    {
        $list = isset($config['storage']) ? $config['storage'] : [];
        $list = is_array($list) ? $list : [$list];
        if (count($list) == 0) {
            $list[] = StaticValues::class;
        }
        foreach ($list as $i => $storageClass) {
            $list[$storageClass] = IndexHelper::storageClassToType($storageClass);
            unset($list[$i]);
        }
        return $list;
    }