code: def extract_async(self, destination, format='csv', csv_delimiter=None, csv_header=True,
                      compress=False):
      
      format = format.upper()
      if format == 'JSON':
        format = 'NEWLINE_DELIMITED_JSON'
      if format == 'CSV' and csv_delimiter is None:
        csv_delimiter = ','
      try:
        response = self._api.table_extract(self._name_parts, destination, format, compress,
                                           csv_delimiter, csv_header)
        return self._init_job_from_response(response)
      except Exception as e:
        raise google.datalab.JobError(location=traceback.format_exc(), message=str(e),
                                      reason=str(type(e)))
docs: Starts a job to export the table to GCS.
  
      Args:
        destination: the destination URI(s). Can be a single URI or a list.
        format: the format to use for the exported data; one of 'csv', 'json', or 'avro'
            (default 'csv').
        csv_delimiter: for CSV exports, the field delimiter to use. Defaults to ','
        csv_header: for CSV exports, whether to include an initial header line. Default true.
        compress: whether to compress the data on export. Compression is not supported for
            AVRO format. Defaults to False.
      Returns:
        A Job object for the export Job if it was started successfully; else None.