code: def test_pickle(self):
      import pickle
  
      for G in self.graphs:
          H = pickle.loads(pickle.dumps(G, -1))
          assert edges_equal(H.edges, G.edges)
          assert nodes_equal(H.nodes, G.nodes)
  
imports: import pytest
  import networkx
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 2 for calling the TestChainsOfViews obj's underlying member method code with example usage: obj.test_pickle() without return types