protected static function detectTitle(array $title)
    {
        $assignment = $title['assignment'];
        if ($assignment === null) {
            return;
        }

        $where = array_merge(
            Utils\Utils::arrayWhitelist($title, [
                'assignment',
                'our_number',
                'due',
            ]),
            [
                'ORDER' => [
                    'stamp' => 'DESC',
                    'id' => 'DESC',
                ],
            ]
        );

        $ids = Models\Title::dump($where, 'id');
        if (empty($ids)) {
            return;
        }
        return $ids[0];
    }