Ouzo\Db\ModelQueryBuilder::with PHP Метод

    public function with($relationSelector)
    {
        $relations = ModelQueryBuilderHelper::extractRelations($this->_model, $relationSelector);
        $field = '';
        foreach ($relations as $relation) {
            $nestedField = $field ? $field . '->' . $relation->getName() : $relation->getName();
            $this->_addRelationToFetch(new RelationToFetch($field, $relation, $nestedField));
            $field = $nestedField;
        }
        return $this;
    }