code: def validate_solution(soln, cost, exp_soln, exp_cost):
      assert soln == exp_soln
      assert cost == exp_cost
  
imports: import random
  import pytest
  import networkx
  import networkx.algorithms.approximation
label_desc: Use image node_id 4 for calling a global function with example usage: validate_solution(soln, cost, exp_soln, exp_cost) without return types