code: def test_nonstationary_series():
      # Test against R stats::ar.yw; see results/results_yw_dl.R
      endog = np.arange(1, 12) * 1.0
      res, _ = durbin_levinson(endog, 2, demean=False)
  
      desired_ar_params = [0.92318534179, -0.06166314306]
      assert_allclose(res[2].ar_params, desired_ar_params)
  
file_path: statsmodels/statsmodels/tsa/arima/estimators/tests/test_durbin_levinson.py
imports: import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_raises
  from statsmodels.tsa.innovations.arma_innovations import arma_innovations
  from statsmodels.tsa.arima.datasets.brockwell_davis_2002 import dowj, lake
  from statsmodels.tsa.arima.estimators.durbin_levinson import durbin_levinson
label_desc: Use image node_id 4 for calling a global function with example usage: test_nonstationary_series() without return types