code: def test_current_flow_closeness_centrality_not_connected(self):
      G = nx.Graph()
      G.add_nodes_from([1, 2, 3])
      with pytest.raises(nx.NetworkXError):
          nx.current_flow_closeness_centrality(G)
  
file_path: networkx/networkx/algorithms/centrality/tests/test_current_flow_closeness.py
imports: import pytest
  import networkx
label_desc: Use image node_id 4 for calling the TestFlowClosenessCentrality obj's underlying member method code with example usage: obj.test_current_flow_closeness_centrality_not_connected() without return types