docstr: Get the best ARIMA model.
docstr_tok: ["Get","the","best","ARIMA","model","."]
code: def get_best_model(self):
      """
      Get the best ARIMA model.
      """
      return self.auto_est.get_best_model()
  
imports: import warnings
  from bigdl.chronos.model.arima import ARIMABuilder, ARIMAModel
  from bigdl.chronos.autots.utils import recalculate_n_sampling
label_desc: Use image node_id 3 for calling the AutoARIMA obj's underlying member method code with example usage: obj.get_best_model() and returns: self