docstr: Edge flow betweenness centrality: K4
docstr_tok: ["Edge","flow","betweenness","centrality",":","K4"]
code: def test_K4_normalized(self):
      """Edge flow betweenness centrality: K4"""
      G = nx.complete_graph(4)
      b = edge_current_flow(G, normalized=False)
      b_answer = dict.fromkeys(G.edges(), 0.75)
      for (s, t), v1 in b_answer.items():
          v2 = b.get((s, t), b.get((t, s)))
          assert v1 == pytest.approx(v2, abs=1e-7)
  
imports: import pytest
  import networkx
  from networkx import approximate_current_flow_betweenness_centrality
  from networkx import edge_current_flow_betweenness_centrality
label_desc: Use image node_id 2 for calling the TestEdgeFlowBetweennessCentrality obj's underlying member method code with example usage: obj.test_K4_normalized() without return types