code: def test_zero_capacity_edges():
      """Address issue raised in ticket #617 by arv."""
      G = nx.DiGraph()
      G.add_edges_from(
          [
              (1, 2, {"capacity": 1, "weight": 1}),
              (1, 5, {"capacity": 1, "weight": 1}),
              (2, 3, {"capacity": 0, "weight": 1}),
              (2, 5, {"capacity": 1, "weight": 1}),
              (5, 3, {"capacity": 2, "weight": 1}),
              (5, 4, {"capacity": 0, "weight": 1}),
              (3, 4, {"capacity": 2, "weight": 1}),
          ]
      )
      G.nodes[1]["demand"] = -1
      G.nodes[2]["demand"] = -1
      G.nodes[4]["demand"] = 2
  
      flowCost, H = nx.network_simplex(G)
      soln = {
          1: {2: 0, 5: 1},
          2: {3: 0, 5: 1},
          3: {4: 2},
          4: {},
          5: {3: 2, 4: 0},
      }
      assert flowCost == 6
      assert nx.min_cost_flow_cost(G) == 6
      assert H == soln
  
imports: import bz2
  import importlib.resources
  import os
  import pickle
  import pytest
  import networkx
label_desc: Use image node_id 18 for calling a global function with example usage: test_zero_capacity_edges() without return types