@cache_readonly
    def cov_params_approx(self):
        return self._cov_params_approx(self._cov_approx_complex_step,
                                       self._cov_approx_centered)
(array) The variance / covariance matrix. Computed using the numerical
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/tsa/statespace/mlemodel.py/MLEResults.cov_params_approx