Hi, all. using PB i wanted to implement some access control check on my copyable objects. so i placed that in getStateToCopyFor, all is ok except when i need to perfom some asynchronous call in that method. ex: (i use twisted 10.1.0) ... def getStateToCopyFor(self, user): state = self.getStateToCopy() d = user.has_perm() # this do an asynchronous call def got_perm(allowed, state): if not allowed: state['secret'] = '' return state d.addCallback(got_perm, state) return d ... here user.has_perm performe a database access so it returns a deferred, but when i return that deferred, i got an error saying that 'state' is not a dict (which is quit normal cause it's a deferred). it seems pb do not handle this case, i know i can put my control logic directly in the view method (where returning a deferred is handled) but this will lead to a lot of code duplication, and i really thought that getStateToCopyFor is made for that purpouse. so i wanted to ask what's the best way to achieve that ? Thankx !