---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-21-73510c9ecfe4> in <module>
      1 fig = my_chart.plotly_figure
----> 2 go.FigureWidget(fig)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\graph_objs\_figurewidget.py in __init__(self, data, layout, frames, skip_invalid, **kwargs)
    594             is invalid AND skip_invalid is False
    595         """
--> 596         super(FigureWidget, self).__init__(data, layout, frames, skip_invalid, **kwargs)
    597 
    598     def add_area(
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basewidget.py in __init__(self, data, layout, frames, skip_invalid, **kwargs)
    115         # with the `layout` constructor parameter of the `widgets.DOMWidget`
    116         # ipywidgets class
--> 117         super(BaseFigureWidget, self).__init__(
    118             data=data,
    119             layout_plotly=layout,
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in __init__(self, data, layout_plotly, frames, skip_invalid, **kwargs)
    524         # The _data property is a list of dicts containing the properties
    525         # explicitly set by the user for each trace.
--> 526         self._data = [deepcopy(trace._props) for trace in data]
    527 
    528         # ### Create data defaults ###
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in __setattr__(self, prop, value)
    719         if prop.startswith("_") or hasattr(self, prop):
    720             # Let known properties and private properties through
--> 721             super(BaseFigure, self).__setattr__(prop, value)
    722         else:
    723             # Raise error on unknown public properties
C:\ProgramData\Anaconda3\lib\site-packages\traitlets\traitlets.py in __set__(self, obj, value)
    583             raise TraitError('The "%s" trait is read-only.' % self.name)
    584         else:
--> 585             self.set(obj, value)
    586 
    587     def _validate(self, obj, value):
C:\ProgramData\Anaconda3\lib\site-packages\traitlets\traitlets.py in set(self, obj, value)
    572             # we explicitly compare silent to True just in case the equality
    573             # comparison above returns something other than True/False
--> 574             obj._notify_trait(self.name, old_value, new_value)
    575 
    576     def __set__(self, obj, value):
C:\ProgramData\Anaconda3\lib\site-packages\traitlets\traitlets.py in _notify_trait(self, name, old_value, new_value)
   1132 
   1133     def _notify_trait(self, name, old_value, new_value):
-> 1134         self.notify_change(Bunch(
   1135             name=name,
   1136             old=old_value,
C:\ProgramData\Anaconda3\lib\site-packages\ipywidgets\widgets\widget.py in notify_change(self, change)
    603             if name in self.keys and self._should_send_property(name, getattr(self, name)):
    604                 # Send new state to front-end
--> 605                 self.send_state(key=name)
    606         super(Widget, self).notify_change(change)
    607 
C:\ProgramData\Anaconda3\lib\site-packages\ipywidgets\widgets\widget.py in send_state(self, key)
    487             state, buffer_paths, buffers = _remove_buffers(state)
    488             msg = {'method': 'update', 'state': state, 'buffer_paths': buffer_paths}
--> 489             self._send(msg, buffers=buffers)
    490 
    491 
C:\ProgramData\Anaconda3\lib\site-packages\ipywidgets\widgets\widget.py in _send(self, msg, buffers)
    735         """Sends a message to the model in the front-end."""
    736         if self.comm is not None and self.comm.kernel is not None:
--> 737             self.comm.send(data=msg, buffers=buffers)
    738 
    739     def _repr_keys(self):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\comm\comm.py in send(self, data, metadata, buffers)
    120     def send(self, data=None, metadata=None, buffers=None):
    121         """Send a message to the frontend-side version of this comm"""
--> 122         self._publish_msg('comm_msg',
    123             data=data, metadata=metadata, buffers=buffers,
    124         )
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\comm\comm.py in _publish_msg(self, msg_type, data, metadata, buffers, **keys)
     63         data = {} if data is None else data
     64         metadata = {} if metadata is None else metadata
---> 65         content = json_clean(dict(data=data, comm_id=self.comm_id, **keys))
     66         self.kernel.session.send(self.kernel.iopub_socket, msg_type,
     67             content,
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in json_clean(obj)
    189         out = {}
    190         for k,v in iteritems(obj):
--> 191             out[unicode_type(k)] = json_clean(v)
    192         return out
    193     if isinstance(obj, datetime):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in json_clean(obj)
    189         out = {}
    190         for k,v in iteritems(obj):
--> 191             out[unicode_type(k)] = json_clean(v)
    192         return out
    193     if isinstance(obj, datetime):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in json_clean(obj)
    189         out = {}
    190         for k,v in iteritems(obj):
--> 191             out[unicode_type(k)] = json_clean(v)
    192         return out
    193     if isinstance(obj, datetime):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in json_clean(obj)
    175 
    176     if isinstance(obj, list):
--> 177         return [json_clean(x) for x in obj]
    178 
    179     if isinstance(obj, dict):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in <listcomp>(.0)
    175 
    176     if isinstance(obj, list):
--> 177         return [json_clean(x) for x in obj]
    178 
    179     if isinstance(obj, dict):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in json_clean(obj)
    189         out = {}
    190         for k,v in iteritems(obj):
--> 191             out[unicode_type(k)] = json_clean(v)
    192         return out
    193     if isinstance(obj, datetime):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in json_clean(obj)
    175 
    176     if isinstance(obj, list):
--> 177         return [json_clean(x) for x in obj]
    178 
    179     if isinstance(obj, dict):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in <listcomp>(.0)
    175 
    176     if isinstance(obj, list):
--> 177         return [json_clean(x) for x in obj]
    178 
    179     if isinstance(obj, dict):
C:\ProgramData\Anaconda3\lib\site-packages\ipykernel\jsonutil.py in json_clean(obj)
    195 
    196     # we don't understand it, it's probably an unserializable object
--> 197     raise ValueError("Can't clean for JSON: %r" % obj)
ValueError: Can't clean for JSON: datetime.date(2017, 1, 1)