code: def _downloadStream(self, fileName, encrypt=True):
          
          blob = self.bucket.get_blob(bytes(fileName), encryption_key=self.sseKey if encrypt else None)
          if blob is None:
              raise NoSuchFileException(fileName)
  
          class DownloadPipe(ReadablePipe):
              def writeTo(self, writable):
                  try:
                      blob.download_to_file(writable)
                  finally:
                      writable.close()
  
          with DownloadPipe() as readable:
              yield readable
docs: Yields a context manager that can be used to read from the bucket
          with a stream. See :class:`~toil.jobStores.utils.WritablePipe` for an example.
  
          :param fileName: name of file in bucket to be read
          :type fileName: str
          :param encrypt: whether or not the file is encrypted
          :type encrypt: bool
          :return: an instance of ReadablePipe.
          :rtype: :class:`~toil.jobStores.utils.ReadablePipe`