--- a/poller-queue.py	Wed May 30 18:26:26 2018 +0800
+++ b/poller-queue.py	Wed May 30 20:46:17 2018 +0800
@@ -70,7 +70,8 @@
             elif target['type'] == 'github':
                 self.parse_github(target, data)
 
-            target['etag'] = response.headers.get('ETag', None)
+            if 'ETag' in response.headers:
+                target['etag'] = response.headers['ETag']
         elif response.code == 304:
             logging.debug('Not modified: %s', target['poll'])
         else: