def _get_row_labels(self, arr):
        try:
            return arr.index
        except __HOLE__:
            # if we've gotten here it's because endog is pandas and
            # exog is not, so just return the row labels from endog
            return self.orig_endog.index
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/base/data.py/PandasData._get_row_labels