def vstackarma_minus1(self):
        a = np.concatenate((self.ar[1:], self.ma[1:]),0)
        return a.reshape(-1, self.nvarall)

    #@property
stack ar and lagpolynomial vertically in 2d array
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/tsa/varma_process.py/VarmaPoly.vstackarma_minus1