docstr: Betweenness centrality: K4
docstr_tok: ["Betweenness","centrality",":","K4"]
code: def test_K4(self):
      """Betweenness centrality: K4"""
      G = nx.complete_graph(4)
      for solver in ["full", "lu", "cg"]:
          b = nx.current_flow_betweenness_centrality(
              G, normalized=False, solver=solver
          )
          b_answer = {0: 0.75, 1: 0.75, 2: 0.75, 3: 0.75}
          for n in sorted(G):
              assert b[n] == pytest.approx(b_answer[n], 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 TestFlowBetweennessCentrality obj's underlying member method code with example usage: obj.test_K4() without return types