code: def test_invalid_matrix():
      nm = np.array(
          [
              [0.1, 0.9],
              [0.9, 0.1],
          ]
      )
      py = [0.1, 0.9]
      assert not noise_generation.noise_matrix_is_valid(nm, py)
  
imports: import numpy
  from cleanlab.benchmarking import noise_generation
  import pytest
label_desc: Use image node_id 9 for calling a global function with example usage: test_invalid_matrix() without return types