PHPOffice / PhpSpreadsheet

        $dateValue = Functions::flattenSingleValue($dateValue);

        $method = Functions::flattenSingleValue($method);

        if (!is_numeric($method)) {

            return Functions::VALUE();

        } elseif (($method < 1) || ($method > 2)) {

            return Functions::NAN();

        }

        $method = floor($method);

        if ($dateValue === null) {

    {

        $aValue = Functions::flattenSingleValue($aValue);

        $style = (is_null($style))    ? 0 :    (integer) Functions::flattenSingleValue($style);

        if ((!is_numeric($aValue)) || ($aValue < 0) || ($aValue >= 4000)) {

            return Functions::VALUE();

        }

        $aValue = (integer) $aValue;

        if ($aValue == 0) {

            return '';