code: def test_bse(self):
      # Cannot compare middle element of bse because we estimate sigma^2
      # rather than sigma
      bse = self.result.cov_params_approx.diagonal() ** 0.5
      assert_allclose(bse[:4], self.true["bse_oim"][:4], atol=1e-6)
      assert_allclose(bse[6:], self.true["bse_oim"][6:], atol=1e-6)
  
imports: import warnings
  import os
  import numpy
  from numpy.testing import assert_equal, assert_allclose
  import pandas
  import pytest
  from statsmodels.tools import add_constant
  from statsmodels.tsa.regime_switching import markov_autoregression
label_desc: Use image node_id 4 for calling the TestHamiltonAR4 obj's underlying member method code with example usage: obj.test_bse() without return types