If I get it right from a quick glance, this would mostly be a drop-in and we'd just need to extendBaseModel most of the time to get runtime validation?

If so, would it be an option to add it toextra_requires as a start - and have it as apip install python-gitlab[pydantic] option for people who'd like to have this? We'd just need some convenient try/except import somewhere, I assume, with a dummy/fallbackBaseModel object or so.