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

        return $this->addUsingAlias(CustomerPeer::FAX, $fax, $comparison);
    }