code: def setup_class(cls):
      cls.x1 = np.array(
          [7.8, 6.6, 6.5, 7.4, 7.3, 7.0, 6.4, 7.1, 6.7, 7.6, 6.8]
      )
      cls.x2 = np.array([4.5, 5.4, 6.1, 6.1, 5.4, 5.0, 4.1, 5.5])
      cls.d1 = DescrStatsW(cls.x1)
      cls.d2 = DescrStatsW(cls.x2)
      cls.cm = CompareMeans(cls.d1, cls.d2)
  
imports: import numpy
  from scipy import stats
  import pandas
  from numpy.testing import assert_, assert_almost_equal, assert_allclose
  from statsmodels.stats.weightstats import DescrStatsW, CompareMeans, ttest_ind, ztest, zconfint
  from statsmodels.tools.testing import Holder
label_desc: Use image node_id 1 for calling the TestZTest obj's underlying member method code with example usage: obj.setup_class(cls) without return types