code: def __init__(
      self,
      lower=-1.6,
      upper=1.6,
      utt2ratio=None,
      dbunit=True,
      seed=None,
  ):
      self.dbunit = dbunit
      self.utt2ratio_file = utt2ratio
      self.lower = lower
      self.upper = upper
      self.state = numpy.random.RandomState(seed)
  
      if utt2ratio is not None:
          # Use the scheduled ratio for each utterances
          self.utt2ratio = {}
          self.lower = None
          self.upper = None
          self.accept_uttid = True
  
          with open(utt2ratio, "r") as f:
              for line in f:
                  utt, ratio = line.rstrip().split(None, 1)
                  ratio = float(ratio)
                  self.utt2ratio[utt] = ratio
      else:
          # The ratio is given on runtime randomly
          self.utt2ratio = None
  
imports: import librosa
  import numpy
  import scipy
  import soundfile
  from espnet.utils.io_utils import SoundHDF5File
label_desc: Use image node_id 1 to create a new VolumePerturbation object from inherited base classes: object with example: obj = VolumePerturbation(lower, upper, utt2ratio, dbunit, seed)