code: function listFiles(auth) {
      var drive = google.drive('v3');
      drive.files.list({
          auth: auth,
          pageSize: 30,
          fields: "nextPageToken, files(id, name)"
      }, function(err, response) {
          if (err) {
              console.log('The API returned an error: ' + err);
              return;
          }
          var files = response.files;
          if (files.length == 0) {
              debug('No files found.');
          } else {
              debug('Files:');
              for (var i = 0; i < files.length; i++) {
                  var file = files[i];
                  debug('%s (%s)', JSON.stringify(file, null, 2), file.name, file.id);
              }
          }
      });
  }
docs: Lists the names and IDs of up to 10 files.
  
  @param {google.auth.OAuth2} auth An authorized OAuth2 client.