code: def test_guerrero_robust_scale(self):
      # The lambda is derived from a manual check of the values for the MAD.
      # Compare also the result for the standard deviation on R=4: 0.5076,
      # i.e. almost the same value.
      lmbda = self.bc._est_lambda(self.x, scale="mad")
      assert_almost_equal(lmbda, 0.488621, 4)
  
file_path: statsmodels/statsmodels/base/tests/test_transform.py
imports: import numpy
  from numpy.testing import assert_almost_equal, assert_equal, assert_raises
  from statsmodels.base.transform import BoxCox
  from statsmodels.datasets import macrodata
label_desc: Use image node_id 7 for calling the TestTransform obj's underlying member method code with example usage: obj.test_guerrero_robust_scale() without return types