/**
  * Finds an appropriate contentunit for the given banner
  *
  * @param Banner $banner
  * @return AppBundle\Entity\Contentunit
  */
 protected function findContentunit(Banner $banner)
 {
     $em = $this->getDoctrine()->getManager();
     return $em->getRepository('AppBundle:Contentunit')->findByImage($banner->getImageFile());
 }