code: def extract_wav(datafile, target=None):
      
      if datafile.endswith(".wav"):
          return datafile
  
      target = target or os.path.dirname(datafile) 
      if os.path.isdir(target):
          target = os.path.join(target, os.path.splitext(os.path.basename(datafile))[0] + ".wav")
  
      if datafile.endswith(".flac"):
          cmd = [config.CMD_FLAC, "--silent", "--decode", "--force", "-o", target, datafile]
      else:
          cmd = [config.CMD_FFMPEG, "-v", "0", "-y", "-i", datafile, "-acodec", "pcm_s16le", "-ac", "2", target]
      subprocess.check_call(cmd, stdout=open(os.devnull, "wb"), stderr=subprocess.STDOUT)
  
      return target
docs: Get LPCM 16bit audio stream from mediafile.
      
          If `target` is a directory, create a .wav with the same basename as the input.
          If target is empty, write to the directory of the source file. Otherwise, use it 
          directly as the target filename.