code: def test_tree_transformer(self):
      tree_transformer = TreeTransformer(self.tree_model)
      assert (
          sum(tree_transformer.n_splits.values())
          == self.n_internal_nodes
      )
      lin_reg = LinearRegression()
      tree_rep = tree_transformer.fit_transform(self.X).get_all_data()
      lin_reg.fit(tree_rep, self.y)
      assert_array_equal(
          lin_reg.predict(tree_rep), self.tree_model.predict(self.X)
      )
  
imports: import copy
  import numpy
  import random
  import scipy
  from sklearn.linear_model import Ridge, LinearRegression
  from sklearn.tree import DecisionTreeRegressor
  from sklearn.ensemble import RandomForestRegressor, RandomForestClassifier
  from sklearn.metrics import r2_score, log_loss, roc_auc_score, mean_squared_error
  from imodels.importance.block_transformers import IdentityTransformer, TreeTransformer, CompositeTransformer, MDIPlusDefaultTransformer
  from imodels.importance.ppms import RidgeRegressorPPM, LogisticClassifierPPM, RobustRegressorPPM
  from imodels.importance.mdi_plus import TreeMDIPlus, ForestMDIPlus
  from imodels.importance.rf_plus import RandomForestPlusClassifier
label_desc: Use image node_id 3 for calling the TestTransformers obj's underlying member method code with example usage: obj.test_tree_transformer() without return types