How to signal shutdown by user code?

I'm implementing a kernel by inheriting from `ipykernel.kernelbase.Kernel`, as described at [Making simple Python wrapper kernels](https://jupyter-client.readthedocs.io/en/latest/wrapperkernels.html).

My `do_execute` method passes code to an external interpreter implemented in a Python module, and it is possible that this code includes an instruction to shut down the interpreter, comparable to `sys.exit(0)` in Python. When that happens, the interpreter raises an exception.

Because after that code the interpreter is no longer usable, I want to catch that exception and in response initiate a kernel shutdown. Unfortunately, I wasn't able to figure out how to do so.

Is it possible to initiate a kernel shutdown from within the kernel? If yes, how?

If not, what is the recommended way to deal with code which shuts down the interpreter? Detecting that from the code might be impossible to do correctly. And even if I could do it, I would still have to initiate shutdown from within `do_execute`.