code: def test_isomorphism_iter1():
      # As described in:
      # http://groups.google.com/group/networkx-discuss/browse_thread/thread/2ff65c67f5e3b99f/d674544ebea359bb?fwc=1
      g1 = nx.DiGraph()
      g2 = nx.DiGraph()
      g3 = nx.DiGraph()
      g1.add_edge("A", "B")
      g1.add_edge("B", "C")
      g2.add_edge("Y", "Z")
      g3.add_edge("Z", "Y")
      gm12 = iso.DiGraphMatcher(g1, g2)
      gm13 = iso.DiGraphMatcher(g1, g3)
      x = list(gm12.subgraph_isomorphisms_iter())
      y = list(gm13.subgraph_isomorphisms_iter())
      assert {"A": "Y", "B": "Z"} in x
      assert {"B": "Y", "C": "Z"} in x
      assert {"A": "Z", "B": "Y"} in y
      assert {"B": "Z", "C": "Y"} in y
      assert len(x) == len(y)
      assert len(x) == 2
  
imports: import importlib.resources
  import os
  import random
  import struct
  import networkx
  from networkx.algorithms import isomorphism
label_desc: Use image node_id 4 for calling a global function with example usage: test_isomorphism_iter1() without return types