---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
File /opt/conda/lib/python3.10/site-packages/traitlets/traitlets.py:656, in TraitType.get(self, obj, cls)
    655 try:
--> 656     value = obj._trait_values[self.name]
    657 except KeyError:
    658     # Check for a dynamic initializer.

KeyError: 'token'

During handling of the above exception, another exception occurred:

TraitError                                Traceback (most recent call last)
Cell In[4], line 1
----> 1 m = mapwidget.Map(center=[20, 0], zoom=2, height='600px')
      2 m

File /opt/conda/lib/python3.10/site-packages/anywidget/widget.py:62, in AnyWidget.__init__(self, *args, **kwargs)
     57 anywidget_traits[_ANYWIDGET_ID_KEY] = t.Unicode(
     58     f"{self.__class__.__module__}.{self.__class__.__name__}",
     59 ).tag(sync=True)
     61 self.add_traits(**anywidget_traits)
---> 62 super().__init__(*args, **kwargs)
     63 _register_anywidget_commands(self)

File /opt/conda/lib/python3.10/site-packages/ipywidgets/widgets/widget.py:506, in Widget.__init__(self, **kwargs)
    503 super().__init__(**kwargs)
    505 Widget._call_widget_constructed(self)
--> 506 self.open()

File /opt/conda/lib/python3.10/site-packages/ipywidgets/widgets/widget.py:525, in Widget.open(self)
    523 """Open a comm to the frontend if one isn't already open."""
    524 if self.comm is None:
--> 525     state, buffer_paths, buffers = _remove_buffers(self.get_state())
    527     args = dict(target_name='jupyter.widget',
    528                 data={'state': state, 'buffer_paths': buffer_paths},
    529                 buffers=buffers,
    530                 metadata={'version': __protocol_version__}
    531                 )
    532     if self._model_id is not None:

File /opt/conda/lib/python3.10/site-packages/ipywidgets/widgets/widget.py:615, in Widget.get_state(self, key, drop_defaults)
    613 for k in keys:
    614     to_json = self.trait_metadata(k, 'to_json', self._trait_to_json)
--> 615     value = to_json(getattr(self, k), self)
    616     if not drop_defaults or not self._compare(value, traits[k].default_value):
    617         state[k] = value

File /opt/conda/lib/python3.10/site-packages/traitlets/traitlets.py:703, in TraitType.__get__(self, obj, cls)
    701     return self
    702 else:
--> 703     return self.get(obj, cls)

File /opt/conda/lib/python3.10/site-packages/traitlets/traitlets.py:673, in TraitType.get(self, obj, cls)
    671 try:
    672     obj._cross_validation_lock = True
--> 673     value = self._validate(obj, default)
    674 finally:
    675     obj._cross_validation_lock = _cross_validation_lock

File /opt/conda/lib/python3.10/site-packages/traitlets/traitlets.py:738, in TraitType._validate(self, obj, value)
    736     return value
    737 if hasattr(self, "validate"):
--> 738     value = self.validate(obj, value)
    739 if obj._cross_validation_lock is False:
    740     value = self._cross_validate(obj, value)

File /opt/conda/lib/python3.10/site-packages/traitlets/traitlets.py:2536, in Unicode.validate(self, obj, value)
   2534         msg = "Could not decode {!r} for unicode trait '{}' of {} instance."
   2535         raise TraitError(msg.format(value, self.name, class_of(obj))) from e
-> 2536 self.error(obj, value)

File /opt/conda/lib/python3.10/site-packages/traitlets/traitlets.py:844, in TraitType.error(self, obj, value, error, info)
    838 else:
    839     e = "The '{}' trait expected {}, not {}.".format(
    840         self.name,
    841         self.info(),
    842         describe("the", value),
    843     )
--> 844 raise TraitError(e)

TraitError: The 'token' trait of a Map instance expected a unicode string, not the NoneType None.