def _correct_fut_stats(fut_mean, fut_std, shift_expanded, scale_expanded):
    """
    Helper function for `predict` that adjusts future statistics by shift and
    scale parameters.

    Parameters
    ----------
    fut_mean : pd.Series, shape (n_samples, )
        Mean calculated using the moving window for each day of the future
        model.
    fut_std : pd.Series, shape (n_samples, )
        Standard deviation calculated using the moving window for each day
        of the future model.
    shift_expanded : pd.Series, shape (n_samples, )
        The value by which to adjust the future mean, repeated over the
        length of the Series.
    scale_expanded : pd.Series, shape (n_samples, )
        The value by which to adjust the future standard deviation, repeated over the
        length of the Series.

    Returns
    -------
    fut_mean_corrected : pd.Series, shape (n_samples, )
        Corrected mean for each day of the future model.
    fut_std_corrected : pd.Series, shape (n_samples, )
        Corrected standard deviation for each day of the future model.
    """
    fut_mean_corrected = fut_mean + shift_expanded
    fut_std_corrected = fut_std * scale_expanded
    return fut_mean_corrected, fut_std_corrected