code: def test_fit(self, **kwargs):
      # Test fitting against Stata
      with warnings.catch_warnings():
          warnings.simplefilter("ignore")
          res = self.model.fit(disp=False, **kwargs)
      assert_allclose(
          res.llf, self.true["llf_fit"], atol=self.atol, rtol=self.rtol
      )
  
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 3 for calling the MarkovAutoregression obj's underlying member method code with example usage: obj.test_fit() without return types