UniversalClassLoader is deprecated.

And you don't need the ClassLoader component. you can add a prefix in the Composer classloader:

```php
// The autoload.php file returns the autoloader instance when being included
// We use require and not require_once to be sure that the file gets included to get the autoloader and not false.
// The file generated by Composer can be included as many times as we want safely (and always return the same instance)
$classLoader = require __DIR__ . '/../vendor/autoload.php';

$classLoader->add('Swift_', __DIR__ . '/../lib/classes');