code: def test_zero_lambda(self):
      # zero lambda should be a log transform.
      y_transform_zero_lambda, lmbda = self.bc.transform_boxcox(
          self.x, 0.0
      )
  
      assert_equal(lmbda, 0.0)
      assert_almost_equal(y_transform_zero_lambda, np.log(self.x), 5)
  
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 10 for calling the TestTransform obj's underlying member method code with example usage: obj.test_zero_lambda() without return types