code: def test_values(self):
      for lag, (y0, ylag) in self.alla:
          assert_equal(y0, self.alle[lag].T)
          assert_equal(y0, ylag + lag)
  
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 2 for calling the CheckPanelLagMixin obj's underlying member method code with example usage: obj.test_values() without return types