def forecast(self, ar=None, ma=None, nperiod=10):
        eta = np.r_[self.error_estimate, np.zeros(nperiod)]
        if ar is None:
            ar = self.ar_est
        if ma is None:
            ma = self.ma_est
        return signal.lfilter(ma, ar, eta)
Checks that all the array have the right size.
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/tsa/arma_mle.py/Arma.forecast--crossover with--dataset/ETHPy150Open enthought/mayavi/mayavi/tools/data_wizards/data_source_wizard.py/DataSourceWizard.check_arrays