code: func PropValAtom(xu *xgbutil.XUtil, reply *xproto.GetPropertyReply,
  	err error) (string, error) {
  
  	if err != nil {
  		return "", err
  	}
  	if reply.Format != 32 {
  		return "", fmt.Errorf("PropValAtom: Expected format 32 but got %d",
  			reply.Format)
  	}
  
  	return AtomName(xu, xproto.Atom(xgb.Get32(reply.Value)))
  }
docs: // PropValAtom transforms a GetPropertyReply struct into an ATOM name.
  // The property reply must be in 32 bit format.