public function denyCorrection(Correction $correction, $comment = null)
    {
        $correction->setCorrectionDenied(true);
        $correction->setCorrectionDeniedComment($comment);
        $this->om->persist($correction);
        $this->om->flush();

        $this->eventDispatcher->dispatch('log', new LogCorrectionReportEvent($correction->getDrop()->getDropzone(), $correction->getDrop(), $correction, $this->roleManager));

        return $correction;
    }