docstr: Tests converting between MIDI values and their frequencies in hertz.
docstr_tok: ["Tests","converting","between","MIDI","values","and","their","frequencies","in","hertz","."]
code: def test_hz_to_midi_is_accurate(self):
      """Tests converting between MIDI values and their frequencies in hertz."""
      hz = np.linspace(0.0, 20000.0, 128)
      librosa_midi = librosa.hz_to_midi(hz)
      librosa_midi = tf.where(tf.less_equal(hz, 0.0), 0.0, librosa_midi)
      tf_midi = core.hz_to_midi(hz)
      self.assertAllClose(librosa_midi, tf_midi)
  
imports: from absl.testing import parameterized
  from ddsp import core
  import librosa
  import numpy
  from scipy import signal
  import tensorflow.compat.v2
label_desc: Use image node_id 2 for calling the UtilitiesTest obj's underlying member method code with example usage: obj.test_hz_to_midi_is_accurate() without return types