code: def test_relabel_nodes_missing(self):
      G = nx.Graph([("A", "B"), ("A", "C"), ("B", "C"), ("C", "D")])
      mapping = {0: "aardvark"}
      # copy=True
      H = nx.relabel_nodes(G, mapping, copy=True)
      assert nodes_equal(H.nodes, G.nodes)
      # copy=False
      GG = G.copy()
      nx.relabel_nodes(G, mapping, copy=False)
      assert nodes_equal(G.nodes, GG.nodes)
  
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 14 for calling the TestRelabel obj's underlying member method code with example usage: obj.test_relabel_nodes_missing() without return types