public function filterBySerial($serial = null, $comparison = null)
    {
        if (null === $comparison) {
            if (is_array($serial)) {
                $comparison = Criteria::IN;
            } elseif (preg_match('/[\%\*]/', $serial)) {
                $serial = str_replace('*', '%', $serial);
                $comparison = Criteria::LIKE;
            }
        }

        return $this->addUsingAlias(LicensePeer::SERIAL, $serial, $comparison);
    }