Revisit python generator templates

[luke-hill]

🤔 What's the problem you've observed?

Need to revisit / tidy these up once #165 is merged

✨ Do you have a proposal for making it better?

Can tidy up some of the ruby here as a lot is going on

📚 Any additional context?

N/A - Make sure messages still builds for python. Get @elchupanebrej to review it if there are minor tweaks