public function getManifest($slug)
    {
        if (! is_null($slug)) {
            $path     = $this->getManifestPath($slug);
            $contents = $this->files->get($path);
            $validate = @json_decode($contents, true);

            if (json_last_error() === JSON_ERROR_NONE) {
                $collection = collect(json_decode($contents, true));

                return $collection;
            }

            throw new Exception('['.$slug.'] Your JSON manifest file was not properly formatted. Check for formatting issues and try again.');
        }
    }