docs: def binary_value_or_stdin(value):
      """
      Return fsencoded value or read raw data from stdin if value is None.
      """
      if value is None:
          reader = io.open(sys.stdin.fileno(), mode='rb', closefd=False)
          return reader.read()
      elif six.PY3:
          return os.fsencode(value)
      else:
          return value