code: def setup_class(cls):
      true = {
          "params": np.r_[
              0.7530865,
              0.6825357,
              0.7641424,
              1.972771,
              0.0790744,
              0.527953,
              0.5895792**2,
              1.605333**2,
          ],
          "llf": -745.7977,
          "llf_fit": -745.7977,
          "llf_fit_em": -745.83654,
          "bse_oim": np.r_[
              0.0634387,
              0.0662574,
              0.0782852,
              0.2784204,
              0.0301862,
              0.0857841,
              np.nan,
              np.nan,
          ],
      }
      super().setup_class(
          true,
          areturns[1:],
          k_regimes=2,
          exog=areturns[:-1],
          switching_variance=True,
      )
  
imports: import os
  import warnings
  import numpy
  from numpy.testing import assert_allclose, assert_raises
  import pandas
  import pytest
  from statsmodels.tsa.regime_switching import markov_switching, markov_regression
label_desc: Use image node_id 1 for calling the TestAreturnsConstL1Variance obj's underlying member method code with example usage: obj.setup_class(cls) without return types