statespace.SARIMAX model: why the model use all the data to train mode, and predict the a range of train model

Question

I followed the tutorial to study the SARIMAX model: https://www.digitalocean.com/community/tutorials/a-guide-to-time-series-forecasting-with-arima-in-python-3. The date range of

Answer 1

The author of the blog set those parameters because: "The output of our code suggests that SARIMAX(1, 1, 1)x(1, 1, 1, 12) yields the lowest AIC."