code: def test_brockwell_davis_example_514():
      # Note: this example is primarily tested in
      # test_burg::test_brockwell_davis_example_514.
  
      # Get the lake data, demean
      endog = lake.copy()
  
      # Yule-Walker
      res, _ = yule_walker(endog, ar_order=2, demean=True)
      assert_allclose(res.ar_params, [1.0538, -0.2668], atol=1e-4)
      assert_allclose(res.sigma2, 0.4920, atol=1e-4)
  
file_path: statsmodels/statsmodels/tsa/arima/estimators/tests/test_yule_walker.py
imports: import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_equal, assert_raises
  from statsmodels.tsa.stattools import acovf
  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.yule_walker import yule_walker
label_desc: Use image node_id 2 for calling a global function with example usage: test_brockwell_davis_example_514() without return types