public function getHighestRow($column = null)
    {
        if ($column == null) {
            $colRow = $this->getHighestRowAndColumn();

            return $colRow['row'];
        }

        $rowList = [0];
        foreach ($this->getCoordinates() as $coord) {
            sscanf($coord, '%[A-Z]%d', $c, $r);
            if ($c != $column) {
                continue;
            }
            $rowList[] = $r;
        }

        return max($rowList);
    }