code: def test_subgraph_mixed(classes):
      cls1, cls2 = classes
      with pytest.raises(ValueError, match=r"kind"):
          cls1().subgraph(cls2())
  
file_path: graphviz/tests/test_graphs.py
imports: import itertools
  import pytest
  import graphviz
label_desc: Use image node_id 14 for calling a global function with example usage: test_subgraph_mixed(classes) without return types