Doctrine query not equal

doctrine.notequal.php

<?php
use Doctrine\Common\Collections\Criteria;

class Classy
{
    public function index()
    {
        $criteria = new Criteria();
        $criteria->where(Criteria::expr()->neq('roles', 'ROLE_USER'));

        $users = $app['orm.em']->getRepository('models\\User')->matching($criteria);

        // ICYM: Making query easy.
        // Finally doctrine realizes we need !=/neq 
    }
}