diff --git a/youtube_dl/extractor/viki.py b/youtube_dl/extractor/viki.py
index 20e8bbf7e..ac199d410 100644
--- a/youtube_dl/extractor/viki.py
+++ b/youtube_dl/extractor/viki.py
@@ -91,7 +91,7 @@ def _real_extract(self, url):
def _get_available_subtitles(self, video_id, info_webpage):
res = {}
- for sturl in re.findall(r''):
+ for sturl in re.findall(r'', info_webpage):
m = re.search(r'/(?P[a-z]+)\.vtt', sturl)
if not m:
continue