def _real_extract(self, url):
        m = re.match(self._VALID_URL, url)
        display_id = m.group('slug')
        webpage = self._download_webpage(url, display_id)
        channel_id = self._html_search_meta('ustream:channel_id', webpage)

        BASE = 'http://www.ustream.tv'
        next_url = channel_id % '/ajax/socialstream/videos/%s/1.json'
        video_ids = []
        while next_url:
            reply = self._download_json(
                compat_urlparse.urljoin(BASE, next_url), display_id,
                note='Downloading video information (next: %d)' % (len(video_ids) + 1))
            video_ids.extend(re.findall(r'data-content-id="(\d.*)"', reply['data']))
            next_url = reply['nextUrl']

        entries = [
            self.url_result('http://www.ustream.tv/recorded/' + vid, 'Ustream')
            for vid in video_ids]
        return {
            '_type': 'playlist',
            'id': channel_id,
            'display_id': display_id,
            'entries': entries,
        }
dataset/ETHPy150Open yasoob/youtube-dl-GUI/youtube_dl/extractor/ustream.py/UstreamChannelIE._real_extract/swapped operands of `%`