code: def test_iterator_vs_iterable():
      G = nx.empty_graph("a")
      assert list(nx.community.label_propagation_communities(G)) == [
          {"a"}
      ]
      for community in nx.community.label_propagation_communities(G):
          assert community == {"a"}
      pytest.raises(
          TypeError, next, nx.community.label_propagation_communities(G)
      )
  
imports: from itertools import chain, combinations
  import pytest
  import networkx
label_desc: Use image node_id 2 for calling a global function with example usage: test_iterator_vs_iterable() without return types