code: def test_reverse_subgraph_toundirected(self):
      G = self.DG.reverse(copy=False)
      SG = G.subgraph([4, 5, 6])
      SSG = SG.to_undirected()
      assert list(SSG) == [4, 5, 6]
      assert sorted(SSG.edges) == [(4, 5), (5, 6)]
  
imports: import pytest
  import networkx
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 8 for calling the TestChainsOfViews obj's underlying member method code with example usage: obj.test_reverse_subgraph_toundirected() without return types