public function writeFile(QtiFile $file)
    {
        try {
            $this->writeString($file->getIdentifier());
        } catch (QtiBinaryStreamAccessException $e) {
            $msg = "An error occured while reading a QTI File.";
            throw new QtiBinaryStreamAccessException($msg, $this, QtiBinaryStreamAccessException::FILE, $e);
        }
    }