CAllCrmActivity::ExtractUrnFromSubject

static function ExtractUrnFromSubject($str)
{
	$str = strval($str);

	if($str === '')
	{
		return '';
	}

	$matches = array();
	if(preg_match(self::$URN_REGEX, $str, $matches) !== 1)
	{
		return '';
	}
	return isset($matches['urn']) ? $matches['urn'] : '';
}