Twisted-list, In an application I'm writing I would like all Perspective Broker clients to share some list of objects and have them all keep in sync when one of the clients updates an object's attributes (imagine say a shared address book - I'm not creating an address book, but it's easier than explaining the details of my app). I've created a pb.Cacheable class for the purposes of notifying clients when new objects are added to this list which works fine (I based this on the cache_classes.py example from the docs here <http://twistedmatrix.com/ projects/core/documentation/howto/pb-copyable.html>). Where I am having trouble is with round trip editing these objects (which are all both pb.Copyable and pb.RemoteCopy - I did this so that I wouldn't have problems of accidentally storing a RemoteFoo object in my ZODB rather than a Foo object). Say one user edits one of the objects (e.g. changes the name/phone number etc. of one of the entries in the shared address book). and then I callRemote to some method like "updateObject" on the users Avatar and pass this object to this method. According to the doc page I mentioned previously "Copyable objects return unchanged from a round trip", but when I check if the object is in the list on the server it thinks it isn't there. In fact, they seem to point to different objects in memory, so naturally a "if object in list" statement will fail. Am I checking for equality in the wrong way? Or am I approaching the problem in the wrong way? I am quite new to Twisted, so I apologise if the problem is obvious. Robert