code: func keyBindGrabs(xu *xgbutil.XUtil, evtype int, win xproto.Window, mods uint16,
  	keycode xproto.Keycode) int {
  
  	xu.KeybindsLck.RLock()
  	defer xu.KeybindsLck.RUnlock()
  
  	key := xgbutil.KeyKey{evtype, win, mods, keycode}
  	return xu.Keygrabs[key] // returns 0 if key does not exist
  }
docs: // keyBindGrabs returns the number of grabs on a particular
  // event/window/mods/keycode combination. Namely, this combination
  // uniquely identifies a grab. If it's repeated, we get BadAccess.
  // The idea is that if there are 0 grabs on a particular (modifiers, keycode)
  // tuple, then we issue a grab request. Otherwise, we don't.
  // This is exported for use in the keybind package. It should not be used.