[Discussion] Help with updating customized templates

I have customised .mustache templates for a python client in the past. For example I have adjusted some of the code in api_client.mustache.
Now I have re-generated the client code and realised that I'll need to update the templates as well because for example a parameter called _spec_property_naming had been added.

Thus I am now left with the template that I had edited and the updated template and would like to merge them. They both are different and I am having a hard time deciding which change was done by me originally what what is just a version update.
Is there a way to make this easier?

I do understand that if I had added comments or committed the original template and then my changes this would be easier...but I haven't 😅

Start by comparing the customized and updated api_client.mustache templates and identify the parts that make user changes difficult to distinguish from generator updates. The issue is complete when it provides or documents a practical way to merge customized templates with updated versions.