David Brochart

The `bump-version.py` script was copied over from Voilà, but I guess it has to be adapted to work here?

I ran "Draft Changelog" on my branch. From [the logs](https://github.com/davidbrochart/jupyter_releaser/runs/3897157553?check_suite_focus=true), it looks like we would need to install JupyterLab in the [draft-changelog action](https://github.com/jupyter-server/jupyter_releaser/blob/master/.github/actions/draft-changelog/action.yml) (because [bump-version.py](https://github.com/jupyter-widgets/ipywidgets/blob/1a6a4cd93e5e879facbcd8bcdcaaaf9f7df6d8d2/scripts/bump-version.py#L30) needs `jlpm`)?

Actually I was missing some [Jupyter Releaser hooks](https://github.com/jupyter-widgets/ipywidgets/blob/24f20c1285844cee2a99457d7e7a37b7323b52d0/pyproject.toml#L27-L30). But the problem is that the [bump-version.py](https://github.com/jupyter-widgets/ipywidgets/blob/24f20c1285844cee2a99457d7e7a37b7323b52d0/scripts/bump-version.py) script needs `lerna` to be installed.

Isn't it because when `link_check` fails, it cancels `check_release`?

Interesting, thanks Ryan. I'm going to try this out with a simple case and report back on how it goes.

Actually it brings up some interesting questions, for instance, how can `allow_none=True` be supported? Since this would translate into the `Optional[...]` static typing annotation, how to apply this conditionally to...

Actually, I'm thinking more and more that we should do things the other way around: not add static typing to a dynamic typing library, but add dynamic typing to static...

I think we could implement the observer pattern on top of pydantic, see https://github.com/davidbrochart/pyceptive. For ipywidgets, I think it would be feasible too.

> a. For example, our friends over at Arviz have a `InferenceData` structure composed of multiple Datasets that is represented on-disk using NetCDF groups: https://arviz-devs.github.io/arviz/notebooks/XarrayforArviZ.html Just a note that this...

As @JohanMabille mentioned, another reason for switching to C++17 is using https://github.com/wjakob/nanobind in xtensor-python instead of pybind11.