code: def _run_test(self, sf):
      sf["target"] = [
          i < sf.num_rows() / 2 for i in range(sf.num_rows())
      ]
  
      for model in [
          tc.regression.boosted_trees_regression,
          tc.classifier.boosted_trees_classifier,
          tc.regression.random_forest_regression,
          tc.classifier.random_forest_classifier,
          tc.regression.decision_tree_regression,
          tc.classifier.decision_tree_classifier,
      ]:
          m = model.create(
              sf, "target", validation_set=None, max_depth=2
          )
          tree = DecisionTree.from_model(m)
          for nid, node in tree.nodes.items():
              val = tree.get_prediction_score(nid)
              if node.is_leaf:
                  self.assertTrue(type(val) in {float, int})
              else:
                  self.assertEqual(val, None)
  
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 PythonDecisionTreeAllModelsTest obj's underlying member method code with example usage: obj._run_test(sf) without return types