class_docstr: Meta data for a kaldi corpus directory. 
class_docstr_tok: ["Meta","data","for","a","kaldi","corpus","directory","."]
code: def __init__(self, extra_files=None):
      self.data_path = None
      self.utts = defaultdict(Utt)
      self.spks = defaultdict(Spk)
      self.files_to_load = [
          ("feats.scp", "feat"),
          ("feats.len", "featlen"),
          ("vad.scp", "vad"),
          ("utt2spk", "spk"),
      ]
      if extra_files:
          logging.info("Adding extra files to load: %s" % (extra_files))
          self.files_to_load.extend(extra_files)
  
file_path: delta/delta/utils/kaldi/kaldi_dir.py
imports: import os
  from collections import defaultdict
  from absl import logging
label_desc: Use image node_id 1 to create a new KaldiMetaData object  with example: obj = KaldiMetaData(extra_files)