docstr: Edge betweenness centrality: balanced tree
docstr_tok: ["Edge","betweenness","centrality",":","balanced","tree"]
code: def test_balanced_tree(self):
      """Edge betweenness centrality: balanced tree"""
      G = nx.balanced_tree(r=2, h=2)
      b = nx.edge_betweenness_centrality(
          G, weight=None, normalized=False
      )
      b_answer = {
          (0, 1): 12,
          (0, 2): 12,
          (1, 3): 6,
          (1, 4): 6,
          (2, 5): 6,
          (2, 6): 6,
      }
      for n in sorted(G.edges()):
          assert b[n] == pytest.approx(b_answer[n], abs=1e-7)
  
imports: import pytest
  import networkx
label_desc: Use image node_id 6 for calling the TestEdgeBetweennessCentrality obj's underlying member method code with example usage: obj.test_balanced_tree() without return types