protected function getEntityAttributeValue(string $key)
    {
        $value = $this->getEntityAttributeRelation($key);

        // In case we are accessing to a multivalued attribute, we will return
        // a collection with pairs of id and value content. Otherwise we'll
        // just return the single model value content as a plain result.
        if ($this->getEntityAttributes()->get($key)->is_collection) {
            return $value->pluck('content');
        }

        return ! is_null($value) ? $value->getAttribute('content') : null;
    }