Newscoop\NewscoopBundle\Services\TopicService::deleteTopic PHP Method

    public function deleteTopic(Topic $topic)
    {
        if ($this->isAttached($topic->getId())) {
            $this->removeTopicFromAllArticles($topic->getId());
        }
        $this->removeTopicFromAllUsers($topic->getId());
        $this->em->remove($topic);
        $this->em->flush();
        $this->em->clear();
        return true;
    }