def jac_predict(self, params):
        from statsmodels.tools.numdiff import approx_fprime_cs

        jaccs_err = approx_fprime_cs(params, self._predict)
        return jaccs_err
jacobian of prediction function using complex step derivative
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/miscmodels/nonlinls.py/NonlinearLS.jac_predict