public static function getSchedulesAClassContentDeletions(EntityManager $em, $exclude_base_element = false)
    {
        $entities = array();
        foreach ($em->getUnitOfWork()->getScheduledEntityDeletions() as $entity) {
            if ($entity instanceof AbstractClassContent &&
                (!$exclude_base_element || !$entity->isElementContent())) {
                $entities[] = $entity;
            }
        }

        return $entities;
    }