[BUG] interpreter segment fault during xdotool.search_windows()

`xdotool` version is 3.20210903.1, `python-libxdo` version is 0.1.2a1
```python
>>> import xdo

>>> x = xdo.Xdo(display=':0')
>>> x.select_window_with_click()
127926279
>>> xdotool.get_pid_window(127926279)
18197
>>> xdotool.search_windows(pid=18197)
[1]    27937 segmentation fault (core dumped)  python
```