Implementing the decorator pattern in Python

Question

I want to implement the decorator pattern in Python, and I wondered if there is a way to write a decorator that just implements the function it wants to modify, without writ

Answer 1

In Python 3, Philipp's accepted answer raised RuntimeError: maximum recursion depth exceeded.

The way that worked for me:

class Foo(object):
    def f1(self):
        print("original f1")

    def f2(self):
        print("original f2")

class FooDecorator(object):
    def __init__(self, decoratee):
        self._decoratee = decoratee

    def f1(self):
        print("decorated f1")
        return self._decoratee.f1()

    def __getattr__(self, name):
        if name in ['f1', '_decoratee']:
            raise AttributeError()
        return getattr(self._decoratee, name)

f = FooDecorator(Foo())
f.f1()
# decorated f1
# original f1
f.f2()
# original f2

The workaround is inspired by Ned Batchelder's blog