code: def setUpClass(cls):
      master_seed(seed=1234)
      super().setUpClass()
  
      cls.sklearn_model = DecisionTreeRegressor()
      cls.classifier = ScikitlearnDecisionTreeRegressor(
          model=cls.sklearn_model
      )
      cls.classifier.fit(x=cls.x_train_diabetes, y=cls.y_train_diabetes)
  
file_path: adversarial-robustness-toolbox/tests/estimators/regression/test_scikitlearn.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  import unittest
  import numpy
  from sklearn.tree import DecisionTreeRegressor
  from art.estimators.regression.scikitlearn import ScikitlearnDecisionTreeRegressor
  from art.estimators.regression.scikitlearn import ScikitlearnRegressor
  from tests.utils import TestBase, master_seed
label_desc: Use image node_id 1 for calling the TestScikitlearnDecisionTreeRegressor obj's underlying member method code with example usage: obj.setUpClass(cls) without return types