private function initWorksheets()
    {
        foreach ($this->file->getAllSheets() as $index => $worksheet) {
            $this->sheets[$index] = new Sheet($worksheet);
        }

        return $this;
    }
private function initWorksheets()
    {
        foreach ($this->file->getAllSheets() as $index => $worksheet) {
            $this->sheets[$index] = new Sheet($worksheet);
        }

        return $this;
    }
private function initWorksheets ( ) { foreach ( $ this -> file -> getAllSheets ( ) as $ index => $ worksheet ) { $ this -> sheets [ $ index ] = new Sheet ( $ worksheet ) ; } return $ this ; }
Initialize the worksheets, by creating a Sheet object for all of them

@return self
Initialize the worksheets by creating a Sheet object for all of them