Add method that dissapeared in a merge

cdplib/db_handlers/MongodbHandler.py

@@ -519,7 +519,7 @@ class MongodbHandler:
         data = self._database[collection_name].find(query,{query_label:1, '_id':0})
         if data.collection.count_documents(query) != 0:
             return [value[query_label] for value in data]
-        else:<
+        else:
             return []