code: def test_edmonds2_maxbranch():
      G = G2()
      x = branchings.maximum_branching(G)
      x_ = build_branching(optimal_branching_2a)
      assert_equal_branchings(x, x_)
  
imports: import math
  from operator import itemgetter
  import pytest
  import networkx
  from networkx.algorithms.tree import branchings, recognition
label_desc: Use image node_id 21 for calling a global function with example usage: test_edmonds2_maxbranch() without return types