Fatal error: Uncaught Error: Class "Symfony\Component\EventDispatcher\EventDispatcher" not found in E:\xampp\htdocs\key1\vendor\symfony\http-kernel\Tests\Fixtures\TestEventDispatcher.php:17 Stack trace: #0 {main} thrown in E:\xampp\htdocs\key1\vendor\symfony\http-kernel\Tests\Fixtures\TestEventDispatcher.php on line 17