code: func PropValStr(reply *xproto.GetPropertyReply, err error) (string, error) {
  	if err != nil {
  		return "", err
  	}
  	if reply.Format != 8 {
  		return "", fmt.Errorf("PropValStr: Expected format 8 but got %d",
  			reply.Format)
  	}
  	return string(reply.Value), nil
  }
docs: // PropValStr transforms a GetPropertyReply struct into a string.
  // Useful when the property value is a null terminated string represented
  // by integers. Also must be 8 bit format.