protected function getRelationship($key)
    {
        if (true === $this->isHasOne($key)) {
            $this->touch();
            return $this->hasOneRelationships->get($key);
        }
        if (true === $this->isHasMany($key)) {
            $this->touch();
            $collection = $this->hasManyRelationships->get($key);
            if ($collection->isLoaded($collection)) {
                return iterator_to_array($collection);
            }
            return (true === $this->collectionAutoInit) ? iterator_to_array($collection) : $collection->allWithoutLoad();
        }
        return null;
    }