code: def test_hz_to_midi():
      assert np.allclose(librosa.hz_to_midi(55), 33)
      assert np.allclose(
          librosa.hz_to_midi([55, 110, 220, 440]), [33, 45, 57, 69]
      )
  
imports: import os
  import sys
  import warnings
  import librosa
  import numpy
  import pytest
label_desc: Use image node_id 18 for calling a global function with example usage: test_hz_to_midi() without return types