code: def test_all_pairs_lca_nonempty_graph_without_lca(self):
      G = nx.DiGraph()
      G.add_node(3)
      ans = list(all_pairs_lca(G))
      assert ans == [((3, 3), 3)]
  
imports: from itertools import chain, combinations, product
  import pytest
  import networkx
label_desc: Use image node_id 11 for calling the TestDAGLCA obj's underlying member method code with example usage: obj.test_all_pairs_lca_nonempty_graph_without_lca() without return types