Run multiple instances of python/different versions of python

[frederik-uni]

the python env is set by PYTHONPATH. Is it possible to use

Python::with_gil(|py| {})

with 2 diffferent python runtimes or 2 different python versions

[davidhewitt]

Unfortunately because PyO3 interacts with an in-process Python, I am not aware of any way to load multiple versions at the same time.

For multiple runtimes, perhaps you are looking for #576