code: def test_relabel_isolated_nodes_to_same(self):
      G = nx.Graph()
      G.add_nodes_from(range(4))
      mapping = {1: 1}
      H = nx.relabel_nodes(G, mapping, copy=False)
      assert nodes_equal(H.nodes(), list(range(4)))
  
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 13 for calling the TestRelabel obj's underlying member method code with example usage: obj.test_relabel_isolated_nodes_to_same() without return types