+class Rebuilder(Visitor):
+ '''Returns a hashable version of the objtree.'''
+
+ def visitAtom(self, obj):
+ return obj
+
+ def visitIterable(self, obj):
+ changed = False
+ newItems = []
+ for oldItem in obj:
+ newItem = self.visit(oldItem)
+ if newItem is not oldItem:
+ changed = True
+ newItems.append(newItem)
+ if changed:
+ klass = type(obj)
+ return klass(newItems)
+ else:
+ return obj
+
+ def visitByteArray(self, obj):
+ return obj
+
+