/**
* @param WorkbookInterface $workbook The parent Workbook where the Sheet will live
* @param PHPExcel_Worksheet $phpExcelWorksheet
*/
public function __construct(Workbook $workbook, PHPExcel_Worksheet $phpExcelWorksheet = null)
{
$this->phpExcelWorksheet = $phpExcelWorksheet ?: new PHPExcel_Worksheet($workbook->getRawClass());
}