diff --git a/swh/lister/bitbucket/tasks.py b/swh/lister/bitbucket/tasks.py
--- a/swh/lister/bitbucket/tasks.py
+++ b/swh/lister/bitbucket/tasks.py
@@ -44,7 +44,7 @@
     random.shuffle(ranges)
     promise = group(range_bitbucket_lister.s(minv, maxv, **lister_args)
                     for minv, maxv in ranges)()
-    self.log.debug('%s OK (spawned %s subtasks)' % (self.name, len(ranges)))
+    self.log.debug('%s OK (spawned %s subtasks)', (self.name, len(ranges)))
     try:
         promise.save()  # so that we can restore the GroupResult in tests
     except (NotImplementedError, AttributeError):
diff --git a/swh/lister/core/indexing_lister.py b/swh/lister/core/indexing_lister.py
--- a/swh/lister/core/indexing_lister.py
+++ b/swh/lister/core/indexing_lister.py
@@ -152,8 +152,6 @@
         t = self.db_session.query(func.min(self.MODEL.indexable)).first()
         if t:
             return t[0]
-        else:
-            return None
 
     def db_last_index(self):
         """Look in the db for the largest indexable value
@@ -164,8 +162,6 @@
         t = self.db_session.query(func.max(self.MODEL.indexable)).first()
         if t:
             return t[0]
-        else:
-            return None
 
     def disable_deleted_repo_tasks(self, start, end, keep_these):
         """Disable tasks for repos that no longer exist between start and end.
@@ -226,11 +222,12 @@
                                 index)
                     return
                 index = next_index
+                logger.debug('Index: %s', index)
                 yield i
 
         for i in ingest_indexes():
             if (i % 20) == 0:
-                logger.info('flushing updates')
+                logger.info('flushing updates at index %s', i)
                 self.db_session.commit()
                 self.db_session = self.mk_session()
 
diff --git a/swh/lister/github/lister.py b/swh/lister/github/lister.py
--- a/swh/lister/github/lister.py
+++ b/swh/lister/github/lister.py
@@ -34,15 +34,12 @@
             reset_at = int(response.headers['X-RateLimit-Reset'])
             delay = min(reset_at - time.time(), 3600)
             return True, delay
-        else:
-            return False, 0
+        return False, 0
 
     def get_next_target_from_response(self, response):
         if 'next' in response.links:
             next_url = response.links['next']['url']
             return int(self.API_URL_INDEX_RE.match(next_url).group(1))
-        else:
-            return None
 
     def transport_response_simplified(self, response):
         repos = response.json()