Review python-client code to prepare for python-3.12

There are lots of breaking changes in python-3.12:

https://docs.python.org/3.12/whatsnew/3.12.html#removed

This issue can be used to track any changes that might be needed to 'python-client' to ensure it will work with future versions of python. We are currently using 3.10 which is no longer under active support, but has security updates until 04 Oct 2026.