docs: def _is_bugged_tarfile(self):
          """
          Check for tar file that tarfile library mistakenly reports as invalid.
          Happens with tar files created on FAT systems.  See:
          http://stackoverflow.com/questions/25552162/tarfile-readerror-file-could-not-be-opened-successfully
          """
          try:
              output = subprocess.check_output(['file', '-z', self.destination]).decode('utf8')
              return 'tar archive' in output and 'gzip compressed data' in output
          except subprocess.CalledProcessError:
              return False