code: def test_jaccard():
      a1 = np.array([True, True, False, False])
      a2 = np.array([True, True, True, True])
      a3 = np.array([False, True, True, False])
      a4 = np.array([False, False, True, True])
  
      assert _jaccard(a1, a1, a1, a1) == 1
      assert _jaccard(a1, a1, a2, a2) == 0.25
      assert _jaccard(a1, a1, a3, a3) == 1.0 / 7
      assert _jaccard(a1, a1, a4, a4) == 0
  
imports: import numpy
  from sklearn.metrics import consensus_score
  from sklearn.metrics.cluster._bicluster import _jaccard
  from sklearn.utils._testing import assert_almost_equal
label_desc: Use image node_id 1 for calling a global function with example usage: test_jaccard() without return types