code: def setup_class(cls):
      vs = Independence()
      family = families.Gaussian()
      np.random.seed(987126)
      Y = np.random.normal(size=100)
      X1 = np.random.normal(size=100)
      X2 = np.random.normal(size=100)
      X3 = np.random.normal(size=100)
      groups = np.kron(np.arange(20), np.ones(5))
  
      D = pd.DataFrame({"Y": Y, "X1": X1, "X2": X2, "X3": X3})
  
      md = GEE.from_formula(
          "Y ~ X1 + X2 + X3", groups, D, family=family, cov_struct=vs
      )
      cls.result1 = md.fit()
  
      cls.result2 = GLM.from_formula("Y ~ X1 + X2 + X3", data=D).fit()
  
imports: import numpy
  import pandas
  from statsmodels.genmod.generalized_linear_model import GLM
  from statsmodels.genmod import families
  from statsmodels.genmod.families import links
  from statsmodels.genmod.generalized_estimating_equations import GEE
  from statsmodels.genmod.cov_struct import Independence
  from numpy.testing import assert_allclose
label_desc: Use image node_id 1 for calling the TestCompareGaussian obj's underlying member method code with example usage: obj.setup_class(cls) without return types