class_docstr: GramVaaniConverter converts the mp3's to wav's for a GramVaani dataset.
  Args:
    target_dir (str): The path to download the data from
    mp3_directory (os.path): The path containing the GramVaani mp3's
  Attributes:
      target_dir (str): The target directory passed as a command line argument
      mp3_directory (os.path): The path containing the GramVaani mp3's
code: def __init__(self, target_dir, mp3_directory):
      self.target_dir = target_dir
      self.mp3_directory = Path(mp3_directory)
  
imports: import csv
  import logging
  import math
  import os
  import subprocess
  import urllib
  from pathlib import Path
  import pandas
  from sox import Transformer
  import swifter
  from deepspeech_training.util.importers import get_importers_parser, get_validate_label
label_desc: Use image node_id 1 to create a new GramVaaniConverter object  with example: obj = GramVaaniConverter(target_dir, mp3_directory)