code: def test_robust_skewness_3d(self, reset_randomstate):
      x = np.random.standard_normal(100)
      x = np.hstack([x, np.zeros(1), -x])
      x = np.tile(x, (10, 10, 1))
      sk_3d = robust_skewness(x, axis=2)
      result = np.zeros((10, 10))
      for sk in sk_3d:
          assert_almost_equal(sk, result)
  
imports: import numpy
  import pandas
  from numpy.testing import assert_almost_equal, assert_raises, assert_equal, assert_allclose
  from statsmodels.stats._adnorm import normal_ad
  from statsmodels.stats.stattools import omni_normtest, jarque_bera, durbin_watson, _medcouple_1d, medcouple, robust_kurtosis, robust_skewness
label_desc: Use image node_id 15 for calling the TestStattools obj's underlying member method code with example usage: obj.test_robust_skewness_3d(reset_randomstate) without return types