Storing objects in session CI 1.7 SVN

[eluser]Unknown[/eluser]
Using CodeIgniter for the first time in over a year. In a previous project, I thought I remembered being able to store objects in sessions. But, when I try to do that with the latest SVN version, I get an error like:

Code:

A PHP Error was encountered

Severity: 4096

Message: Object of class Person could not be converted to string

Filename: libraries/Session.php

Line Number: 683

Searching the forums I found a couple examples of people saying they were able to store objects in sessions. Is this a bug or are objects no longer able to be stored in sessions?