code: def setup_class(cls):
      cls.gind = np.repeat([0, 1, 2], 5)
      cls.mlag = 5
      x = np.arange(15)
      x += 10**cls.gind
      cls.x = x[:, None]
      # expected result
      cls.alle = {
          0: np.array(
              [
                  [
                      1,
                      2,
                      3,
                      4,
                      5,
                      15,
                      16,
                      17,
                      18,
                      19,
                      110,
                      111,
                      112,
                      113,
                      114,
                  ]
              ]
          ),
          1: np.array(
              [[2, 3, 4, 5, 16, 17, 18, 19, 111, 112, 113, 114]]
          ),
          2: np.array([[3, 4, 5, 17, 18, 19, 112, 113, 114]]),
          3: np.array([[4, 5, 18, 19, 113, 114]]),
          4: np.array([[5, 19, 114]]),
      }
      cls.calculate()
  
file_path: statsmodels/statsmodels/stats/tests/test_groups_sw.py
imports: import numpy
  from numpy.testing import assert_equal, assert_raises
  import statsmodels.stats.sandwich_covariance
  from statsmodels.tools.grouputils import GroupSorted
label_desc: Use image node_id 1 for calling the TestBalanced obj's underlying member method code with example usage: obj.setup_class(cls) without return types