must::registerMetadataParser

static function registerMetadataParser($host, $parserClassName)
{
	if(!class_exists($parserClassName) || !is_subclass_of($parserClassName, 'BitrixMainUrlPreviewParser'))
	{
		throw new ArgumentException('Parser class must extend BitrixMainUrlPreviewParser', 'parserClassName');
	}

	static::$metadataParsersByHost[$host] = $parserClassName;
}