code: def test_criterion(shadow_dec_tree):
      assert shadow_dec_tree.criterion() == "Gini"
  
imports: import joblib
  import numpy
  import pytest
  from sklearn.tree import DecisionTreeRegressor, DecisionTreeClassifier
  from dtreeviz.models.sklearn_decision_trees import ShadowSKDTree
label_desc: Use image node_id 8 for calling a global function with example usage: test_criterion(shadow_dec_tree) without return types