def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def _check_sigint_gate_is_correct(self):
        assert (
            self._threads_ignoring_sigint >= 0
        ), "This should never happen, someone must have modified the counter outside of SignalHandler."