code: def test_voterank_emptygraph(self):
      G = nx.Graph()
      assert [] == nx.voterank(G)
  
file_path: networkx/networkx/algorithms/centrality/tests/test_voterank.py
imports: import networkx
label_desc: Use image node_id 2 for calling the TestVoteRankCentrality obj's underlying member method code with example usage: obj.test_voterank_emptygraph() without return types