Laravel seed, relacionando models

 $filename = $file['filename'];  

    private function fillDealerships(array $files)
    {
        foreach ($files as $file) {
            $data = $this->getFileContent($file);

            foreach ($data as $item) {
                $slug = isset($item['u']) ? Str::slug($item['u']) : $file['filename'];
                $filename = $file['filename'];

                /* @var $dealership Dealership */
                $dealership = Dealership::query()->updateOrCreate([
                    'slug' => $slug,
                ], [
                    'name' => $item['n'] ?? $slug,
                ]);

                // Brands()
                if (isset($filename)) {
                    $dealership->brands();
                }

                $this->fillDealershipStore($dealership, $relation = null, $item);
            }
        }
    }