I recently added a PR to enable support for Python 3.13 and 3.14: https://github.com/googleapis/python-documentai-toolbox/pull/390/changes

Typically we would also update the sample tests to test the versions we support. But the sample infrastrcture seems non-standard (the noxfile has a lot of warnings to not edit it, and it's not clear where it would be generated from)

I'll leave it up to the repo owners to manage the samples, but wanted to leave this report for future consideration