code: public Dataset updateDataset(String datasetName, String newDescription) {
      // [START bigquery_update_dataset_description]
      Dataset oldDataset = bigquery.getDataset(datasetName);
      DatasetInfo datasetInfo = oldDataset.toBuilder().setDescription(newDescription).build();
      Dataset newDataset = bigquery.update(datasetInfo);
      // [END bigquery_update_dataset_description]
      return newDataset;
    }
docs: [VARIABLE "some_new_description"]