code: func ActivePID(pid int32, args ...int) error {
  	var hwnd int
  	if len(args) > 0 {
  		hwnd = args[0]
  	}
  
  	internalActive(pid, hwnd)
  	return nil
  }
docs: // ActivePID active the window by PID,
  //
  // If args[0] > 0 on the Windows platform via a window handle to active