docs: def _get_log_file_data_as_encoded_content():
      """Gzip and base64 encode files and BytesIO buffers.
  
      This method gets the log files created by SUM based
      firmware update and tar zip the files.
      :returns: A gzipped and base64 encoded string as text.
      """
      with io.BytesIO() as fp:
          with tarfile.open(fileobj=fp, mode='w:gz') as tar:
              for f in OUTPUT_FILES:
                  if os.path.isfile(f):
                      tar.add(f)
  
          fp.seek(0)
          return base64.encode_as_bytes(fp.getvalue())