code: def log_likelihood_css_arma(self, diffedy):
          
          # need to copy diffedy to a double[] for Java
          likelihood =  self._jmodel.logLikelihoodCSSARMA(_py2java_double_array(self._ctx, diffedy))
          return _java2py(self._ctx, likelihood)
docs: log likelihood based on conditional sum of squares. In contrast to logLikelihoodCSS the array
          provided should correspond to an already differenced array, so that the function below
          corresponds to the log likelihood for the ARMA rather than the ARIMA process
          
          Parameters
          ----------
          diffedY:
              differenced array as a numpy array
          
          returns log likelihood of ARMA as a double