Part of twisted.spread.jelly View Source
If you have written a Copyable class that you expect your client to be receiving, write a local "copy" class to represent it, then call:
Call this at the module level immediately after its class definition. MyCopier should be a subclass of RemoteCopy.
The classname may be a special tag returned by 'Copyable.getTypeToCopyFor' rather than an actual classname.
This call is also for cached classes, since there will be no overlap. The rules are the same.