class_docstr: A data helper for Mel Spectrograms.
code: def data_to_waves(self, data):
      return self.specgrams_helper.melspecgrams_to_waves(data)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from magenta.models.gansynth.lib import datasets
  from magenta.models.gansynth.lib import train_util
  from magenta.models.gansynth.lib.specgrams_helper import SpecgramsHelper
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the DataMelHelper obj's underlying member method code with example usage: obj.data_to_waves(data) and returns: self