code: def test_preflow_push_makes_enough_space():
      # From ticket #1542
      G = nx.DiGraph()
      nx.add_path(G, [0, 1, 3], capacity=1)
      nx.add_path(G, [1, 2, 3], capacity=1)
      R = preflow_push(G, 0, 3, value_only=False)
      assert R.graph["flow_value"] == 1
  
imports: import pytest
  import networkx
  from networkx.algorithms.flow import boykov_kolmogorov, build_flow_dict, build_residual_network, dinitz, edmonds_karp, preflow_push, shortest_augmenting_path
label_desc: Use image node_id 6 for calling a global function with example usage: test_preflow_push_makes_enough_space() without return types