code: def test_in_positives():
      mat = sp.csr_matrix(np.array([[0, 1], [1, 0]])).astype(np.float32)
  
      assert not _lightfm_fast.__test_in_positives(
          0, 0, _lightfm_fast.CSRMatrix(mat)
      )
      assert _lightfm_fast.__test_in_positives(
          0, 1, _lightfm_fast.CSRMatrix(mat)
      )
  
      assert _lightfm_fast.__test_in_positives(
          1, 0, _lightfm_fast.CSRMatrix(mat)
      )
      assert not _lightfm_fast.__test_in_positives(
          1, 1, _lightfm_fast.CSRMatrix(mat)
      )
  
imports: import numpy
  import scipy.sparse
  from lightfm import _lightfm_fast
label_desc: Use image node_id 1 for calling a global function with example usage: test_in_positives() without return types