Python generator changed in v6.2.0

https://github.com/OpenAPITools/openapi-generator/releases/tag/v6.2.0 changed the python generator being used.

!22 (merged) switched to using python-prior to maintain compatibility.

Investigate the impact of this change on the generated client and knock-on effects on tools and APIs that use it.

Propose a solution to allow for use of the new generator going forward.