code: def test_wf_improved(self):
      G = nx.union(self.P4, nx.path_graph([4, 5, 6]))
      c = nx.closeness_centrality(G)
      cwf = nx.closeness_centrality(G, wf_improved=False)
      res = {
          0: 0.25,
          1: 0.375,
          2: 0.375,
          3: 0.25,
          4: 0.222,
          5: 0.333,
          6: 0.222,
      }
      wf_res = {
          0: 0.5,
          1: 0.75,
          2: 0.75,
          3: 0.5,
          4: 0.667,
          5: 1.0,
          6: 0.667,
      }
      for n in G:
          assert c[n] == pytest.approx(res[n], abs=1e-3)
          assert cwf[n] == pytest.approx(wf_res[n], abs=1e-3)
  
file_path: networkx/networkx/algorithms/centrality/tests/test_closeness_centrality.py
imports: import pytest
  import networkx
label_desc: Use image node_id 2 for calling the TestClosenessCentrality obj's underlying member method code with example usage: obj.test_wf_improved() without return types