def _real_extract(self, url):
mobj = re.match(self._VALID_URL, url)
song_id = mobj.group('id')
- info_url = "http://ex.fm/api/v3/song/%s" % song_id
+ info_url = 'http://ex.fm/api/v3/song/%s' % song_id
info = self._download_json(info_url, song_id)['song']
song_url = info['url']
if re.match(self._SOUNDCLOUD_URL, song_url) is not None: