gistfile1.py

bad_attrs = ('__class__', '__doc__', '__init__', '__new__',
             '__getattr__', '__getattribute__', '__subclasshook__',
             '__str__', '__repr__', '__hash__', '__setattr__')

good_attrs = ('append',)


def get_ops(o):
    ops = [x for x in dir(o) if
           (x.startswith('__') and x not in bad_attrs) or
           x in good_attrs]
    return ops

ops = set(get_ops([]) + get_ops({}) + get_ops(()) + get_ops(1) + get_ops(""))


def caller_maker(op):
    def caller(self, *args):
        return getattr(self.val, op)(*args)

    caller.func_name = op
    return caller


def OpDecorator(cls):
    for op in ops:
        setattr(cls, op, caller_maker(op))
    return cls


@OpDecorator
class Faker(object):
    def __init__(self):
        self.val = None

i1, i2 = Faker(), Faker()
i1.val = 1
i2.val = 3

#assert i1 + i2 == 3

assert i1 + 1 == 2
assert 1 + i1 == 2

i1.val = []
i1.append(1)
assert len(i1) == 1
assert i1[0] == 1

What about the simple statement:

i1