Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Spreadsheet.php
public function createSheet($sheetIndex = null)
    {
        $newSheet = new Worksheet($this);
        $this->addSheet($newSheet, $sheetIndex);

        return $newSheet;
    }
public function createSheet($sheetIndex = null)
    {
        $newSheet = new Worksheet($this);
        $this->addSheet($newSheet, $sheetIndex);

        return $newSheet;
    }
Create sheet and add it to this workbook.

@param null|int $sheetIndex Index where sheet should go (0,1,..., or null for last)

@throws Exception

@return Worksheet