code: def test_two_class_nofraczero():
      trace = 1.1
      nm = noise_generation.generate_noise_matrix_from_trace(
          K=2,
          trace=trace,
          valid_noise_matrix=True,
      )
      assert not np.any(
          nm == 0
      )  # Make sure there is not a zero noise rate.
      assert abs(trace - np.trace(nm) < 1e-2)
  
imports: import numpy
  from cleanlab.benchmarking import noise_generation
  import pytest
label_desc: Use image node_id 14 for calling a global function with example usage: test_two_class_nofraczero() without return types