code: def test_composite_transformer(self):
      composite_transformer = CompositeTransformer(
          [IdentityTransformer(), IdentityTransformer()]
      )
      X0_doubled = composite_transformer.fit_transform_one_feature(
          self.X, 0, center=False
      )
      assert X0_doubled.shape[1] == 2
  
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 4 for calling the TestTransformers obj's underlying member method code with example usage: obj.test_composite_transformer() without return types