Warning: Undefined variable $loader in C:\xampp\htdocs\astra-backoffice\vendor\symfony\routing\Tests\Fixtures\validresource.php on line 5

Fatal error: Uncaught Error: Call to a member function import() on null in C:\xampp\htdocs\astra-backoffice\vendor\symfony\routing\Tests\Fixtures\validresource.php:5 Stack trace: #0 {main} thrown in C:\xampp\htdocs\astra-backoffice\vendor\symfony\routing\Tests\Fixtures\validresource.php on line 5