// Print the names and IDs for up to 10 files.
    $optParams = array(
      'pageSize' => 10,
      'fields' => 'nextPageToken, files(id, name)'
    );
    $results = $service->files->listFiles($optParams);

    if (count($results->getFiles()) == 0) {
      print "No files found.n";
    } else {
      print "Files:n";
      foreach ($results->getFiles() as $file) {
        printf("%s (%s)n<br>", $file->getName(), $file->getId());

      }
    }