Subtract the {0} of two {1} objects.

        Parameters
        ----------
        other: an {1} fitted instance.

def subtract(self, other):
        """
        Subtract the {0} of two {1} objects.

        Parameters
        ----------
        other: an {1} fitted instance.
        """
        self_estimate = getattr(self, self._estimate_name)
        other_estimate = getattr(other, other._estimate_name)
        new_index = np.concatenate((other_estimate.index, self_estimate.index))
        new_index = np.unique(new_index)
        return pd.DataFrame(
            self_estimate.reindex(new_index, method="ffill").values
            - other_estimate.reindex(new_index, method="ffill").values,
            index=new_index,
            columns=["diff"],
        )