Adding exception handling for when inserting many documents when some of them are invalid

cdplib/db_handlers/MongodbHandler.py

@@ -244,7 +244,7 @@ class MongodbHandler:
                 self._log.warning(('An error occured inserting {} documents into database: {} and collection: {}.').format(len(data), self._database_name, collection_name))
                 self._log.warning('This might be because one or more documents are invalid.') 
                 self._log.warning('We will try to insert the documents one-by-one and report which are invalid.')
-                self._log.warning('Error: {}').format(error)
+                self._log.warning(('Error: {}').format(error))
                 for row in data:
                     try:
                         self._database[collection_name].insert_one(row)