/usr/lib/python3/dist-packages/IPython/html/widgets/ is in ipython3-notebook 2.3.0-2.
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/usr/lib/python3/dist-packages/IPython/html/widgets/__init__.py
/usr/lib/python3/dist-packages/IPython/html/widgets/interaction.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_bool.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_button.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_container.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_float.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_image.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_int.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_selection.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_selectioncontainer.py
/usr/lib/python3/dist-packages/IPython/html/widgets/widget_string.py