title: use pydub for convert to WAV
body: <p>I want use pydub (Python script)  to convert m4a file and mp3 file to WAV file (with <strong>attributes A-Law, 8000Hz, 64kbps, mono.</strong>)</p>
  <p>I tried, but this converted file has data in unknown format.</p>
  <p>Any suggestions?</p>