code: def setUpClass(self):
      sf = tc.SFrame(
          {
              "cat1": ["1", "1", "2", "2", "2"] * 100,
              "cat2": ["1", "3", "3", "1", "1"] * 100,
              "target": ["1", "2", "1", "2", "1"] * 100,
          }
      )
      model = tc.classifier.boosted_trees_classifier.create(
          sf, "target", validation_set=None, max_depth=2
      )
      tree = DecisionTree.from_model(model)
      self.tree = tree
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import unittest
  import turicreate
  from turicreate.toolkits._decision_tree import DecisionTree, Node
  from turicreate.toolkits._main import ToolkitError
label_desc: Use image node_id 1 for calling the PythonDecisionTreeTest obj's underlying member method code with example usage: obj.setUpClass() without return types