def download(audio, output, title):
    """Download audio

    :param audio: hash
    :param output: string 
    """
    if not os.path.exists(output):
        os.makedirs(output)
    r = requests.get(audio['url'])

    filename = title % '%s.mp3'
    if os.path.isfile(filename):
        return None

    with open(os.path.join(output, filename), 'wb') as f:
        for buf in r.iter_content(1024):
            if buf:
                f.write(buf)
dataset/ETHPy150Open korzhyk/VKMusic/vkmusic/runner.py/download/swapped operands of `%`