protected function getStorage()
    {
        if (! $this->storage) {
            $storage = $this->getServiceLocator()->get(Storage::SERVICE_ID);
            if (! $storage instanceof PaginatedStorage) {
                throw new StorageException(__('The storage service provided to store the diagnostic results must be upgraded to support reads!'));
            }
            $this->storage = $storage;
        }
        return $this->storage;
    }