docs: def pp_hex(raw, reverse=True):
      """Return a pretty-printed (hex style) version of a binary string.
  
      Args:
          raw (bytes): any sequence of bytes
          reverse (bool): True if output should be in reverse order.
  
      Returns:
          Hex string corresponding to input byte sequence.
      """
      if not reverse:
          return ''.join(['{:02x}'.format(v) for v in bytearray(raw)])
      return ''.join(reversed(['{:02x}'.format(v) for v in bytearray(raw)]))