code: def test_empty(self):
      G = nx.DiGraph()
      c = harmonic_centrality(G, distance="weight")
      d = {}
      assert c == d
  
file_path: networkx/networkx/algorithms/centrality/tests/test_harmonic_centrality.py
imports: import pytest
  import networkx
  from networkx.algorithms.centrality import harmonic_centrality
label_desc: Use image node_id 10 for calling the TestClosenessCentrality obj's underlying member method code with example usage: obj.test_empty() without return types