public function parentRelations(array $relations): ModelList
    {
        $this->main['parents'] = [];

        foreach ($relations as $key => $value) {

            if (is_string($key)) {
                $parent = [
                    'relation' => $key,
                    'field'    => $value,
                ];
            } else {
                $parent = [
                    'relation' => $value,
                    'field'    => $value,
                ];
            }

            $this->main['parents'][] = $parent;
        }

        return $this;
    }