How to wrap a phpexcel class?

Question

Habr

Hello!
Recently I read this article on Habré: habrahabr.ru/post/136540 .
I can't use this function on my local:

public function getCellValue($cellOrCol, $row = null, $format = 'd.m.Y')
    {
        //column set by index
        if(is_numeric($cellOrCol)) {
            $cell = $this->activeSheet->getCellByColumnAndRow($cellOrCol, $row);
        } else {
            $lastChar = substr($cellOrCol, -1, 1);
            if(!is_numeric($lastChar)) { //column contains only letter, e.g. "A"
               $cellOrCol .= $row;
            } 
            
            $cell = $this->activeSheet->getCell($cellOrCol);
        }
        
        //try to find current coordinate in all merged cells ranges
        //if find -> get value from head cell
        foreach($this->mergedCellsRange as $currMergedRange){
            if($cell->isInRange($currMergedRange)) {
                $currMergedCellsArray = PHPExcel_Cell::splitRange($currMergedRange);
                $cell = $this->activeSheet->getCell($currMergedCellsArray[0][0]);
                break;
            }
        }

        //simple value
        $val = $cell->getValue();
        
        //date
        if(PHPExcel_Shared_Date::isDateTime($cell)) {
             $val = date($format, PHPExcel_Shared_Date::ExcelToPHP($val)); 
        }
        
        //for incorrect formulas take old value
        if((substr($val,0,1) === '=' ) && (strlen($val) > 1)){
            $val = $cell->getOldCalculatedValue();
        }

        return $val;
    }

Please tell me how to use it? The author uses his own phpexcel wrapper class. I am newbie. And I don't really understand how it's done. I couldn't do it on my own. Thank you in advance