class_docstr: VC Tacotron2 module for VC.
  
  This is a module of Tacotron2-based VC model,
  which convert the sequence of acoustic features
  into the sequence of acoustic features.
code: def _sort_by_length(self, xs, ilens):
      sort_ilens, sort_idx = ilens.sort(0, descending=True)
      return xs[sort_idx], ilens[sort_idx], sort_idx
  
imports: import logging
  from distutils.util import strtobool
  import numpy
  import torch
  import torch.nn.functional
  from espnet.nets.pytorch_backend.e2e_tts_tacotron2 import Tacotron2Loss
  from espnet.nets.pytorch_backend.e2e_tts_tacotron2 import GuidedAttentionLoss
  from espnet.nets.pytorch_backend.rnn.attentions import AttForward, AttForwardTA, AttLoc
  from espnet.nets.pytorch_backend.tacotron2.cbhg import CBHG, CBHGLoss
  from espnet.nets.pytorch_backend.tacotron2.decoder import Decoder
  from espnet.nets.pytorch_backend.tacotron2.encoder import Encoder
  from espnet.nets.tts_interface import TTSInterface
  from espnet.utils.fill_missing_args import fill_missing_args
label_desc: Use image node_id 7 for calling the Tacotron2 obj's underlying member method code with example usage: obj._sort_by_length(xs, ilens) and returns: xs,  ilens,  sort_idx