code: func WmWindowTypeSet(xu *xgbutil.XUtil, win xproto.Window,
  	atomNames []string) error {
  
  	atoms, err := xprop.StrToAtoms(xu, atomNames)
  	if err != nil {
  		return err
  	}
  	return xprop.ChangeProp32(xu, win, "_NET_WM_WINDOW_TYPE", "ATOM", atoms...)
  }
docs: // _NET_WM_WINDOW_TYPE set
  // This will create any atoms used in 'atomNames' if they don't already exist.