SESSIONS: store an OBJECT in php4 sessions?

I came across this comment in someone else's PHP code for a shopping cart: // Initialize the Cart. // We can't store an object in PHP4 sessions, so instead we store the list of articles // instead, and "start" a new Cart every time. Isn't it true that we CAN store an object in a php4 session now? (This app, above, was written while php4 was in beta.) If so, HOW would you do it, as it applies to a shopping cart? Any pointers to a tutorial about it anywhere? Thanks! Derek Sivers list@hitmedia.com