code: def test_cutoff(self):
      k = 5
      p = 1000
      G = nx.DiGraph()
      for i in range(k):
          G.add_edge("s", (i, 0), capacity=2)
          nx.add_path(G, ((i, j) for j in range(p)), capacity=2)
          G.add_edge((i, p - 1), "t", capacity=2)
      R = shortest_augmenting_path(
          G, "s", "t", two_phase=True, cutoff=k
      )
      assert k <= R.graph["flow_value"] <= (2 * k)
      R = shortest_augmenting_path(
          G, "s", "t", two_phase=False, cutoff=k
      )
      assert k <= R.graph["flow_value"] <= (2 * k)
      R = edmonds_karp(G, "s", "t", cutoff=k)
      assert k <= R.graph["flow_value"] <= (2 * k)
      R = dinitz(G, "s", "t", cutoff=k)
      assert k <= R.graph["flow_value"] <= (2 * k)
      R = boykov_kolmogorov(G, "s", "t", cutoff=k)
      assert k <= R.graph["flow_value"] <= (2 * k)
  
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 1 for calling the TestCutoff obj's underlying member method code with example usage: obj.test_cutoff() without return types