May be slightly refactor the code?

    def _select_from(self, parent_path, is_dir, exists, listdir):
        try:
            if not is_dir(parent_path):
                return
            yield from self._select_from2(parent_path, is_dir, exists, listdir)
        except PermissionError:
            return

    def _select_from2(self, parent_path, is_dir, exists, listdir):
        ... # implementation