class Delegator:

# The cache is only used to be able to change delegates!

def __init__(self, delegate=None):
self.delegate = delegate
self.__cache = set()

def __getattr__(self, name):
attr = getattr(self.delegate, name) # May raise AttributeError
setattr(self, name, attr)
self.__cache.add(name)
return attr

def resetcache(self):
for key in self.__cache:
try:
delattr(self, key)
except AttributeError:
pass
self.__cache.clear()

def setdelegate(self, delegate):
self.resetcache()
self.delegate = delegate