public function computeDropScore(Drop $drop)
    {
        $corrections = $drop->getCorrections();
        $score = 0;
        $nbValidCorrection = 0;

        foreach ($corrections as $correction) {
            if ($correction->isFinished() && $correction->isValid()) {
                $score += $correction->getScore();
                ++$nbValidCorrection;
            }
        }
        $score = $nbValidCorrection > 0 ? round($score / $nbValidCorrection, 2) : null;
        $drop->setScore($score);
        $this->om->persist($drop);
        $this->om->flush();

        return $drop;
    }