<?phpnamespacePhpOffice\PhpSpreadsheet\Writer;usePhpOffice\PhpSpreadsheet\Spreadsheet;interfaceIWriter{/** * IWriter constructor. * * @param Spreadsheet $spreadsheet */publicfunction__construct(Spreadsheet$spreadsheet);/** * Save PhpSpreadsheet to file. * * @param string $pFilename Name of the file to save * * @throws \PhpOffice\PhpSpreadsheet\Writer\Exception */publicfunctionsave($pFilename);}