public function modify($relative)
    {
        if (preg_match('/hour|minute|second/', $relative)) {
            return $this;
        }
        $new = parent::modify($relative);
        if ($new->format('H:i:s') !== '00:00:00') {
            return $new->setTime(0, 0, 0);
        }

        return $new;
    }