protected static function hexToUnicode($char){

		if(!is_string($char) || !preg_match('(^[0-9a-f]{2,6}$)i', $char)){
			throw new \InvalidArgumentException('$char must be one single unicode character as hex string');
		}

		return mb_convert_encoding('&#x'.strtolower($char).';', 'UTF-8', 'HTML-ENTITIES');

	}