private function replaceQueueFailer()
    {
        $this->app->extend(
            'queue.failer',
            function ($concrete, $app) {
                $collection = $app['config']['queue.failed.collection'];

                return isset($collection)
                    ? $this->buildMongolidFailedJobProvider($app, $collection)
                    : new NullFailedJobProvider();
            }
        );
    }