def reindex(self, index=None, names=None):
        # NOTE: this isn't of much use if the rest of the data doesn't change
        # This needs to reset cache
        if names is None:
            names = self.group_names
        self = Grouping(index, names)
Resets the index in-place.
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/tools/grouputils.py/Grouping.reindex