def oldest_frame(self, raw=False):
        if raw:
            return self.buffer.values[:, self._oldest_frame_idx(), :]
        return self.buffer.iloc[:, self._oldest_frame_idx(), :]
Then step decorator.
dataset/ETHPy150Open quantopian/zipline/zipline/utils/data.py/MutableIndexRollingPanel.oldest_frame--crossover with--dataset/ETHPy150Open pytest-dev/pytest-bdd/pytest_bdd/steps.py/then