docstr: Normalize tokens by handling CTC blank, ASG replabels, etc.
code: def get_tokens(self, idxs):
      """Normalize tokens by handling CTC blank, ASG replabels, etc."""
      idxs = (g[0] for g in it.groupby(idxs))
      idxs = filter(lambda x: x != self.blank, idxs)
      return torch.LongTensor(list(idxs))
  
imports: import gc
  import itertools
  import os.path
  from typing import List
  import warnings
  from collections import deque, namedtuple
  import numpy
  import torch
  from examples.speech_recognition.data.replabels import unpack_replabels
  from fairseq import tasks
  from fairseq.utils import apply_to_sample
  from omegaconf import open_dict
  from fairseq.dataclass.utils import convert_namespace_to_omegaconf
label_desc: Use image node_id 4 for calling the W2lDecoder obj's underlying member method code with example usage: obj.get_tokens(idxs) and returns: torch