protected function parseForCommonValues($relation)
    {
        if (!$this->hasAttribute($relation)) {
            // If no attribute exists for this relationships
            // we'll make it a simple empty array. This will
            // save us from constantly checking for the attributes
            // actual existence.
            $this->relationships[$relation] = [];

            return false;
        }

        $value = $this->getRelationshipValue($relation);

        if (is_null($value)) {
            $this->relationships[$relation] = [];

            // If the relationship's content is the null value
            // and the Entity's exist in DB, we'll interpret this
            // as the need to detach all related Entities,
            // therefore a sync operation is needed.
            $this->needSync[] = $relation;

            return false;
        }

        return $value;
    }