You mean for running unsafe Python code?

I'm on a multi-year quest to answer that question!

The best I've found is running Python code inside Pyodide in WASM in Node.js or Deno accessed from Python via a subprocess, which is a wildly convoluted way to go but does appear to work! https://til.simonwillison.net/deno/pyodide-sandbox

Here's a related recent experimental library which does something similar but with JavaScript rather than Python as the unsafe language, again via Deno in a subprocess: https://github.com/simonw/denobox

I've also experimented with using wasmtime instead of Deno: https://til.simonwillison.net/webassembly/python-in-a-wasm-s...