code: def setup_class(cls):
      true = {
          "params": np.r_[
              0.6378175,
              0.1306295,
              0.724457,
              -0.0988764,
              0.7631424,
              1.061174,
              0.6915759**2,
          ],
          "llf": -264.71069,
          "llf_fit": -264.71069,
          "llf_fit_em": -264.71153,
          "bse_oim": np.r_[
              0.1202616,
              0.0495924,
              0.2886657,
              0.1183838,
              0.0337234,
              0.0185031,
              np.nan,
          ],
      }
      super().setup_class(
          true, fedfunds[1:], k_regimes=2, exog=fedfunds[:-1]
      )
  
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 TestFedFundsConstL1 obj's underlying member method code with example usage: obj.setup_class(cls) without return types