audio files with multiple channels not supported _ problem solve

I use other library making sound segmentation. 
But i have a problem like behind. 

Input: cultoo.wav

Output: /speaker-diarization/lna/cultoo.lna

exception: AudioReader: sorry, audio files with multiple channels not supported

Traceback (most recent call last):

  File "./generate_exp.py", line 264, in <module>

    shift_dec_bord(lnas, arguments['--exppath'])

  File "./generate_exp.py", line 181, in shift_dec_bord

    num_models, l = _read_lna(lna)

  File "./generate_exp.py", line 123, in _read_lna
    with open(lna, 'r') as f:

That time, you solve easily like behind. 
You have to use ffmpeg and -ac option.

 ffmpeg -i cultoo.wav  -ac 1 cultoo.wav