PHPExcel：具有最高细胞的最佳范围细胞

I want to export an excel array with optimal format. So I search the highest cell :

$highestRow = $objPHPExcel->getActiveSheet()->getHighestRow(); 

$highestColumn = $objPHPExcel->getActiveSheet()->getHighestColumn();

$highestcell=($highestColumn.$highestRow); 

And now I want to applicate the style to the range of cells (A2:$highestCell)

$objPHPExcel->getActiveSheet()->getStyle('A2:$highestcell')->applyFromArray($styleArray2); 

The problem is that getStyle is only for one cell or a range of cells (A1:B1) for example. So how can I resolve my problem to have an optimal format for my Excel sheet.

Any suggestions would be helpful, thanks. Corentin

Edit : I found the solution, just getStyle('A2:'$highestcell)