code: def test_is_classifier(xgb_tree):
      assert xgb_tree.is_classifier() == True
  
imports: import joblib
  import numpy
  import pytest
  import xgboost
  from dtreeviz.models.xgb_decision_tree import ShadowXGBDTree
label_desc: Use image node_id 16 for calling a global function with example usage: test_is_classifier(xgb_tree) without return types