docs: def _close_writable(self):
          """
          Close the object in write mode.
          """
          # Wait parts upload completion
          for part in self._write_futures:
              part['ETag'] = part.pop('response').result()['ETag']
  
          # Complete multipart upload
          with _handle_client_error():
              try:
                  self._client.complete_multipart_upload(
                      MultipartUpload={'Parts': self._write_futures},
                      UploadId=self._upload_args['UploadId'],
                      **self._client_kwargs)
              except _ClientError:
                  # Clean up if failure
                  self._client.abort_multipart_upload(
                      UploadId=self._upload_args['UploadId'],
                      **self._client_kwargs)
                  raise