code: def test_relabel_toposort(self):
      K5 = nx.complete_graph(4)
      G = nx.complete_graph(4)
      G = nx.relabel_nodes(G, {i: i + 1 for i in range(4)}, copy=False)
      assert nx.is_isomorphic(K5, G)
      G = nx.complete_graph(4)
      G = nx.relabel_nodes(G, {i: i - 1 for i in range(4)}, copy=False)
      assert nx.is_isomorphic(K5, G)
  
imports: import pytest
  import networkx
  from networkx.generators.classic import empty_graph
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 16 for calling the TestRelabel obj's underlying member method code with example usage: obj.test_relabel_toposort() without return types