Forecasting univariate time series data with exponential smoothing

In this recipe, you will explore the exponential smoothing technique using the statsmodels library. The ExponentialSmoothing classes in statsmodels resemble popular implementations from the R forecast package, such as ets() and HoltWinters(). In statsmodels, there are three different implementations (classes) of exponential smoothing, depending on the nature of the data you are working with:

• SimpleExpSmoothing: Simple exponential smoothing is used when the time series process lacks seasonality and trend. This is also referred to as single exponential smoothing.
• Holt: Holt's exponential smoothing is an enhancement of the simple exponential smoothing and is used when the time series process contains only trend (but no seasonality). It is referred to as double exponential smoothing.
• ExponentialSmoothing: Holt-Winters' exponential smoothing is an enhancement of Holt's exponential smoothing...