def teardown(self) -> None:
        """Restores the signals that were previously configured before :class:`_SignalConnector` replaced them."""
        for signum, handler in self._original_handlers.items():
            if handler is not None:
                self._register_signal(signum, handler)
        self._original_handlers = {}
Restores the signals that were previously configured before :class:`_SignalConnector` replaced them.
src/lightning/pytorch/trainer/connectors/signal_connector.py