code: def test_classes(xgb_tree):
      assert np.array_equal(xgb_tree.classes(), np.array([0, 1]))
  
imports: import joblib
  import numpy
  import pytest
  import xgboost
  from dtreeviz.models.xgb_decision_tree import ShadowXGBDTree
label_desc: Use image node_id 14 for calling a global function with example usage: test_classes(xgb_tree) without return types