code: def test_disconnected_graph(method):
      # This tests the following disconnected graph:
      #     (0) --5--> (1)    (2) --3--> (3)
      graph = csr_matrix(
          [[0, 5, 0, 0], [0, 0, 0, 0], [0, 0, 9, 3], [0, 0, 0, 0]]
      )
      res = maximum_flow(graph, 0, 3, method=method)
      assert res.flow_value == 0
      expected_flow = np.zeros((4, 4), dtype=np.int32)
      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 12 for calling a global function with example usage: test_disconnected_graph(method) without return types