Error running custom anywidget with shinywidget — "RuntimeError: module 'ipykernel' has no attribute 'version_info'"

[psychemedia]

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I a tryin to run a custom anywidget using shinywidgets and get an error when that seems to arise from a broken shim around a missing ipykernelpackage:

Error starting app!
Traceback (most recent call last):
  File "/lib/python3.12/site-packages/traitlets/traitlets.py", line 632, in get
    value = obj._trait_values[self.name]
            ~~~~~~~~~~~~~~~~~^^^^^^^^^^^
KeyError: 'layout'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/lib/python3.12/site-packages/ipywidgets/widgets/widget.py", line 615, in get_state
    value = to_json(getattr(self, k), self)
                    ^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/traitlets/traitlets.py", line 687, in __get__
    return t.cast(G, self.get(obj, cls))  # the G should encode the Optional
                     ^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/traitlets/traitlets.py", line 635, in get
    default = obj.trait_defaults(self.name)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/traitlets/traitlets.py", line 1897, in trait_defaults
    return t.cast(Sentinel, self._get_trait_default_generator(names[0])(self))
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/traitlets/traitlets.py", line 602, in default
    return t.cast(G, self.make_dynamic_default())
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/ipywidgets/widgets/trait_types.py", line 409, in make_dynamic_default
    return self.klass(*(self.default_args or ()),
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/ipywidgets/widgets/widget_layout.py", line 86, in __init__
    super().__init__(**kwargs)
  File "/lib/python3.12/site-packages/ipywidgets/widgets/widget.py", line 506, in __init__
    self.open()
  File "/lib/python3.12/site-packages/ipywidgets/widgets/widget.py", line 535, in open
    self.comm = comm.create_comm(**args)
                ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/ipywidgets/comm.py", line 28, in create_comm
    if requires_ipykernel_shim():
       ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/ipywidgets/comm.py", line 11, in requires_ipykernel_shim
    version = ipykernel.version_info
              ^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'ipykernel' has no attribute 'version_info'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<exec>", line 393, in _start_app
  File "<exec>", line 366, in __init__
  File "/lib/python3.12/site-packages/shiny/express/_run.py", line 62, in wrap_express_app
    app_module = importlib.import_module(package_name)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python312.zip/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "/lib/python3.12/site-packages/shiny/express/_run.py", line 102, in exec_module
    module.app = create_express_app(  # pyright: ignore[reportAttributeAccessIssue]
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/shiny/express/_run.py", line 132, in create_express_app
    app_ui = run_express(file, package_name).tagify()
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.12/site-packages/shiny/express/_run.py", line 255, in run_express
    raise RuntimeError(e) from e
RuntimeError: module 'ipykernel' has no attribute 'version_info'

I'm not sure if this relates to the previously fixed https://github.com/jupyter-widgets/ipywidgets/issues/3819 ?