Fatal error: Uncaught Error: Class "PhpOffice\PhpSpreadsheet\Calculation\CalculationBase" not found in D:\xampp\htdocs\vendor\phpoffice\phpspreadsheet\Calculation\CalculationLocale.php:5 Stack trace: #0 {main} thrown in D:\xampp\htdocs\vendor\phpoffice\phpspreadsheet\Calculation\CalculationLocale.php on line 5