Fatal error: Uncaught Error: Class 'PhpOffice\PhpSpreadsheet\Calculation\Database\DatabaseAbstract' not found in D:\xampp\htdocs\psp\backend\vendor\phpoffice\phpspreadsheet\src\PhpSpreadsheet\Calculation\Database\DVar.php:8 Stack trace: #0 {main} thrown in D:\xampp\htdocs\psp\backend\vendor\phpoffice\phpspreadsheet\src\PhpSpreadsheet\Calculation\Database\DVar.php on line 8