[Pharo-project] Multiple worlds

Hello This issue http://code.google.com/p/pharo/issues/detail?id=3545 is about the feature of having multiple worlds. Status is 'Accepted'. I assume it is now in Pharo 1.4. How can I use it. The code I found from Sean is "Add a world:" WorldManager instance createOrSwitchToWorldNamed: 'JustAnotherWorld'. "Return to the default world:" WorldManager instance createOrSwitchToWorldNamed: 'Pharo'. What are the proper instructions? Thanks in advance Hannes