public function info($row, $col, $type = '', $sheet = 0)
    {
        $col = $this->getCol($col);
        if (array_key_exists('cellsInfo', $this->sheets[$sheet])
            && array_key_exists($row, $this->sheets[$sheet]['cellsInfo'])
            && array_key_exists($col, $this->sheets[$sheet]['cellsInfo'][$row])
            && array_key_exists($type, $this->sheets[$sheet]['cellsInfo'][$row][$col])) {
            return $this->sheets[$sheet]['cellsInfo'][$row][$col][$type];
        }
        return "";
    }