properly deal with unknown url short codes

screenless/bureau/publications/publications.py

@@ -115,12 +115,14 @@ class Publications(Bureau):
         """
         shortcode, _ = data.split(".")
         with self.dbenv.begin(db=self.urldb) as txn:
-            print("looking up short-code:", shortcode)
-            url = txn.get(shortcode.encode('utf-8')).decode()
+            self.log.debug("looking up short-code:" + shortcode)
+            url = txn.get(shortcode.encode('utf-8'))
 
         if not url:
-            print("ERROR: no valid URL in db for short code: ", shortcode)
+            self.log.warning("no valid URL in db for short code: " + shortcode)
             return
+        else:
+            url = url.decode()
 
         # download
         headers = {'User-Agent': 'Mozilla/5.0'}