code: def mel_to_hertz(mel_values):
      """Converts frequencies in `mel_values` from the mel scale to linear scale."""
      return _MEL_BREAK_FREQUENCY_HERTZ * (
          np.exp(np.array(mel_values) / _MEL_HIGH_FREQUENCY_Q) - 1.0
      )
  
file_path: magenta/magenta/models/gansynth/lib/spectral_ops.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling a global function with example usage: mel_to_hertz(mel_values) and returns: unknown