def _apply_to_column_groupbys(self, func):
        return func(self)
Like the name says.  But who knows how it works?
dataset/ETHPy150Open pydata/pandas/pandas/core/groupby.py/SeriesGroupBy._apply_to_column_groupbys--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/appengine-flask-skeleton/lib/werkzeug/_internal.py/_easteregg