def METHOD_NAME(cdf_, ultimate_, is_cumulative=True):
    """ Private method that builds full expectation"""
    full = ultimate_ / cdf_
    if is_cumulative:
        return concat((full, ultimate_.copy().rename("development", [9999])), axis=3)
    else:
        tail_ = full.iloc[:, :, :, -1] - ultimate_
        return concat(
            (full.cum_to_incr(), tail_.copy().rename("development", [9999])), axis=3
        )