code: def test_boost_example(self):
      # Graph taken from Figure 1 of
      # http://www.boost.org/doc/libs/1_56_0/libs/graph/doc/lengauer_tarjan_dominator.htm
      edges = [
          (0, 1),
          (1, 2),
          (1, 3),
          (2, 7),
          (3, 4),
          (4, 5),
          (4, 6),
          (5, 7),
          (6, 4),
      ]
      G = nx.DiGraph(edges)
      assert nx.dominance_frontiers(G, 0) == {
          0: set(),
          1: set(),
          2: {7},
          3: {7},
          4: {4, 7},
          5: {7},
          6: {4},
          7: set(),
      }
      # Test postdominance.
      result = nx.dominance_frontiers(G.reverse(copy=False), 7)
      expected = {
          0: set(),
          1: set(),
          2: {1},
          3: {1},
          4: {1, 4},
          5: {1},
          6: {4},
          7: set(),
      }
      assert result == expected
  
imports: import pytest
  import networkx
label_desc: Use image node_id 9 for calling the TestDominanceFrontiers obj's underlying member method code with example usage: obj.test_boost_example() without return types