Rollback one iteration.

        Returns
        -------
        self : Booster
            Booster with rolled back one iteration.

def rollback_one_iter(self):
        """Rollback one iteration.

        Returns
        -------
        self : Booster
            Booster with rolled back one iteration.
        """
        _safe_call(_LIB.LGBM_BoosterRollbackOneIter(
            self.handle))
        self.__is_predicted_cur_iter = [False for _ in range_(self.__num_dataset)]
        return self