code: def test_greedy_max1():
      # Standard test.
      #
      G = G1()
      B = branchings.greedy_branching(G)
      # There are only two possible greedy branchings. The sorting is such
      # that it should equal the second suboptimal branching: 1b.
      B_ = build_branching(greedy_subopt_branching_1b)
      assert_equal_branchings(B, B_)
  
imports: import math
  from operator import itemgetter
  import pytest
  import networkx
  from networkx.algorithms.tree import branchings, recognition
label_desc: Use image node_id 12 for calling a global function with example usage: test_greedy_max1() without return types