[Python] How to decorate a class?

How do I create a decorator that applies to classes?

Specifically, I want to use a decorator addID to add a member __id to a class, and change the constructor __init__ to take an id argument for that member.

def getId(self): return self.__id

class decorator addID(cls):
def __init__(self, id, *args, **kws):
self.__id = id
self.getId = getId
cls.__init__(self, *args, **kws)

@addID
class Foo:
def __init__(self, value1):
self.value1 = value1


The above should be equivalent to:

class Foo:
def __init__(self, id, value1):
self.__id = id
self.value1 = value1

def getId(self): return self.__id

Continue reading...