code: def approx_aic(self, ts):
          
          return self._jmodel.approxAIC(_py2java(self._ctx, Vectors.dense(ts)))
docs: Calculates an approximation to the Akaike Information Criterion (AIC). This is an approximation
          as we use the conditional likelihood, rather than the exact likelihood. Please see
          [[https://en.wikipedia.org/wiki/Akaike_information_criterion]] for more information on this
          measure.
          
          Parameters
          ----------
          ts:
              the timeseries to evaluate under current model
              
          Returns an approximation to the AIC under the current model as a double