def holtWintersConfidenceArea(requestContext, seriesList, delta=3):
    """
    Performs a Holt-Winters forecast using the series as input data and plots
    the area between the upper and lower bands of the predicted forecast
    deviations.
    """
    bands = holtWintersConfidenceBands(requestContext, seriesList, delta)
    results = areaBetween(requestContext, bands)
    for series in results:
        series.name = series.name.replace('areaBetween',
                                          'holtWintersConfidenceArea')
    return results

    Performs a Holt-Winters forecast using the series as input data and plots
    the area between the upper and lower bands of the predicted forecast
    deviations.
    
graphite_api/functions.py