code: def pack_zero(string, size=4):
      if len(string) < size:
          string = "0" * (size - len(string)) + string
      return string
  
file_path: espnet/egs2/nit_song070/svs1/local/data_prep.py
imports: import argparse
  import os
  import librosa
  import numpy
  import soundfile
  from espnet2.fileio.score_scp import SingingScoreWriter
label_desc: Use image node_id 4 for calling a global function with example usage: pack_zero(string, size) and returns: string