code: def test_flow_func_not_callable(self):
      elements = ["this_should_be_callable", 10, {1, 2, 3}]
      G = nx.Graph()
      G.add_weighted_edges_from(
          [(0, 1, 1), (1, 2, 1), (2, 3, 1)], weight="capacity"
      )
      for flow_func in interface_funcs:
          for element in elements:
              pytest.raises(
                  nx.NetworkXError,
                  flow_func,
                  G,
                  0,
                  1,
                  flow_func=element,
              )
              pytest.raises(
                  nx.NetworkXError,
                  flow_func,
                  G,
                  0,
                  1,
                  flow_func=element,
              )
  
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 2 for calling the TestMaxFlowMinCutInterface obj's underlying member method code with example usage: obj.test_flow_func_not_callable() without return types