public function exist(string $identifier, string $fileExtension = '')
    {
        $fileName = $this->getCacheFileName($identifier);
        $cachePath = $this->cacheFolderWithNamespace.'/'.$fileName;

        if (!empty($fileExtension)) {
            $cachePath .= '.'.$fileExtension;
        }
        $file = new File($cachePath);

        if ($file->exists()) {
            return true;
        }

        return false;
    }