def get_wm_class(self):
        """Return an (instance, class) tuple if WM_CLASS exists."""
        r = self.get_property("WM_CLASS", "STRING")
        if r:
            s = self._property_string(r)
            return list(s.strip("\0").split("\0"))
        return []
Return an (instance, class) tuple if WM_CLASS exists.
libqtile/backend/x11/window.py