code: def __iter__(self):
      for f in self.filelists:
          feat = get_feature(f)
          if self.label == "phoneme":
              label = read_timit_phoneme(f[:-4] + ".PHN")
          elif self.label == "letter":
              label = read_timit_txt(f[:-4] + ".TXT")
          yield [feat, label]
  
imports: import argparse
  import numpy
  import os
  import string
  import bob.ap
  import scipy.io.wavfile
  from tensorpack.dataflow import DataFlow, LMDBSerializer
  from tensorpack.utils import fs, logger, serialize, get_tqdm
  from tensorpack.utils.argtools import memoized
  from tensorpack.utils.stats import OnlineMoments
label_desc: Use image node_id 3 for calling the RawTIMIT obj's underlying member method code with example usage: obj.__iter__() without return types