Fatal error: Uncaught Error: Class "PHPCompatibility\Sniff" not found in /var/www/html/upload/PhpSpreadsheet-master/vendor/phpcompatibility/php-compatibility/PHPCompatibility/Sniffs/Variables/ForbiddenThisUseContextsSniff.php:51 Stack trace: #0 {main} thrown in /var/www/html/upload/PhpSpreadsheet-master/vendor/phpcompatibility/php-compatibility/PHPCompatibility/Sniffs/Variables/ForbiddenThisUseContextsSniff.php on line 51