code: def test_simple_graph(method):
      # This graph looks as follows:
      #     (0) --5--> (1)
      graph = csr_matrix([[0, 5], [0, 0]])
      res = maximum_flow(graph, 0, 1, method=method)
      assert res.flow_value == 5
      expected_flow = np.array([[0, 5], [-5, 0]])
      assert_array_equal(res.flow.toarray(), expected_flow)
  
imports: import numpy
  from numpy.testing import assert_array_equal
  import pytest
  from scipy.sparse import csr_matrix, csc_matrix
  from scipy.sparse.csgraph import maximum_flow
  from scipy.sparse.csgraph._flow import _add_reverse_edges, _make_edge_pointers, _make_tails
label_desc: Use image node_id 8 for calling a global function with example usage: test_simple_graph(method) without return types