Find out if PyPy and/or PyPy's sandbox would be useful to increase security.
A good good candidate for testing and confinement, because relatively simple to play with, would be url_to_unixtime (T102). Later also control-port-filter-python.
See also:
Related:
PyPy's sandbox is an experimental proof-of-concept and will not be operational any time soon.
The project's dev's comments point out that even the only python module that worked with it, the 'time' module, no longer does and was removed. To support a decent amount of python features a lot of work is needed in addition to long-term maintenance investment.
https://stackoverflow.com/a/29890408
systemd.exec integrates and exposes Linux's security features in an easy to use manner. It was chosen instead.