The wrapper checks for a HTTP 403 Response from the server for the first time on every API call. If the server returns 403, the wrapper attempts to login again. During this login, if a callback function is passed by the user the new session_data is passed on to this callback parameter. session_data is a dict object which is returned by client.session_data field. Session Data needs to be stored locally on the client's end (database/redis/file/etc).