code: def test_empty_graph(self):
      G = nx.empty_graph(self.N)
      truth = {frozenset([i]) for i in G}
      self._check_communities(G, truth)
  
imports: from itertools import chain, combinations
  import pytest
  import networkx
label_desc: Use image node_id 3 for calling the TestFastLabelPropagationCommunities obj's underlying member method code with example usage: obj.test_empty_graph() without return types