code: def test_empty_graph():
      G = nx.Graph()
      G.add_nodes_from(range(5))
      expected = [{0}, {1}, {2}, {3}, {4}]
      assert nx.community.louvain_communities(G) == expected
  
file_path: networkx/networkx/algorithms/community/tests/test_louvain.py
imports: import networkx
label_desc: Use image node_id 13 for calling a global function with example usage: test_empty_graph() without return types