protected function initialize()
    {
        $this->injectionContainer = new InjectionContainer();

        $model = $this->newModelInstance();

        // The model instance must be an instance of `Model` class from
        // `Laravel`, otherwise just throw an exception.
        if (! $model instanceof Model) {
            throw new RepositoryException(
                "Class \"" . get_class($model) . "\" must be an instance of " . Model::class
            );
        }

        // Load configures from `housekeeper.php` or just use default settings.
        $this->perPage = $this->getConfig('housekeeper.paginate.per_page', 15);
    }