diff --git a/youtube_dl/downloader/common.py b/youtube_dl/downloader/common.py
index b3206cdc2..7b349c792 100644
--- a/youtube_dl/downloader/common.py
+++ b/youtube_dl/downloader/common.py
@@ -370,7 +370,7 @@ class FileDownloader(object):
         timer = [None]
         heartbeat_lock = None
         download_complete = False
-        if 'heartbeat_url'in info_dict:
+        if 'heartbeat_url' in info_dict:
             heartbeat_lock = threading.Lock()
 
             heartbeat_url = info_dict['heartbeat_url']