--- a/server/python/junius/proto/skype.py
+++ b/server/python/junius/proto/skype.py
@@ -137,17 +137,17 @@ class TwistySkype(object):
         logger.info("Chat %r has %d items to process", chatname,
                     len(remaining))
         logger.debug("we've already seen %d items from this chat",
                      len(seen_chats))
         return self.conductor.coop.coiterate(
                     self.gen_items(chat, remaining, msgs_by_id))
 
     def gen_items(self, chat, todo, msgs_by_id):
-        tow = []
+        tow = [] # documents to write.
         for _, msgid in todo:
             if msgid is None:
                 # we haven't seen the chat itself - do that.
                 logger.debug("Creating new skype chat %r", chat.Name)
                 # make a 'deferred list' to fetch each property one at a time.
                 ds = [threads.deferToThread(chat._Property, p)
                       for p, _ in CHAT_PROPS]
                 yield defer.DeferredList(ds