code: def test_difference_raise():
      G = nx.path_graph(4)
      H = nx.path_graph(3)
      pytest.raises(nx.NetworkXError, nx.difference, G, H)
      pytest.raises(nx.NetworkXError, nx.symmetric_difference, 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 12 for calling a global function with example usage: test_difference_raise() without return types