code: def test_mvsk(self):
      # compare defining mvsk with numerical integration, generic stats
      mvsk2 = self.dist2.mvsk
      mvsk1 = self.dist2.stats(moments="mvsk")
      assert_allclose(mvsk2, mvsk1, rtol=1e-6, atol=1e-13)
  
      # check mvsk that was used to generate distribution
      assert_allclose(self.dist2.mvsk, self.mvsk, rtol=1e-12)
  
file_path: statsmodels/statsmodels/sandbox/distributions/tests/test_norm_expan.py
imports: import pytest
  import numpy
  from scipy import stats
  from numpy.testing import assert_allclose, assert_array_less
  from statsmodels.sandbox.distributions.extras import NormExpan_gen
label_desc: Use image node_id 2 for calling the CheckExpandNorm obj's underlying member method code with example usage: obj.test_mvsk() without return types