protected function saveFile($source) {
    $name = basename($source);
    $path = realpath(DRUPAL_ROOT . '/' . $source);
    $uri = file_unmanaged_copy($path, 'public://' . $name, FILE_EXISTS_REPLACE);
    $file = File::create(['uri' => $uri]);
    $file->save();
    return $file;
  }