You can clone with
Status: Support for functions implemented
This is low-hanging fruit, especially now that classmethods have been done.
eggs = spam(eggs)
but with eggs being stored in a temporary variable rather than the given scope. There is a little trickery because function are not actually defined on the fly at runtime, but it shouldn't be too bad.
StefanBehnel: The funny thing is that class decorators should even be easier to implement than function decorators.