code: def test_is_isomorphic(self):
      assert iso.is_isomorphic(self.G1, self.G2)
      assert not iso.is_isomorphic(self.G1, self.G4)
      assert iso.is_isomorphic(
          self.G1.to_directed(), self.G2.to_directed()
      )
      assert not iso.is_isomorphic(
          self.G1.to_directed(), self.G4.to_directed()
      )
      with pytest.raises(
          nx.NetworkXError,
          match="Graphs G1 and G2 are not of the same type.",
      ):
          iso.is_isomorphic(self.G1.to_directed(), self.G1)
  
file_path: networkx/networkx/algorithms/isomorphism/tests/test_isomorphism.py
imports: import pytest
  import networkx
  from networkx.algorithms import isomorphism
label_desc: Use image node_id 5 for calling the TestIsomorph obj's underlying member method code with example usage: obj.test_is_isomorphic() without return types