code: def test_mixed_type_union():
      G = nx.Graph()
      H = nx.MultiGraph()
      pytest.raises(nx.NetworkXError, nx.union, G, H)
      pytest.raises(nx.NetworkXError, nx.disjoint_union, G, H)
      pytest.raises(nx.NetworkXError, nx.intersection, G, H)
      pytest.raises(nx.NetworkXError, nx.difference, G, H)
      pytest.raises(nx.NetworkXError, nx.symmetric_difference, G, H)
      pytest.raises(nx.NetworkXError, nx.compose, G, H)
  
imports: import os
  import pytest
  import networkx
  from networkx.classes.tests import dispatch_interface
  from networkx.utils import edges_equal
label_desc: Use image node_id 20 for calling a global function with example usage: test_mixed_type_union() without return types