gistfile1.py

def selfdec(f):
    def dec(*x, **kwa):
        f.__globals__['self'] = x[0]
        return f(*x[1:], **kwa)
    return dec

class X():
    @selfdec
    def z(more, args, even="opt"):
        self.hurr = 3
        return "%s: %d" %(even, self.hurr + more + args)

a = X()
print a.z(1,2,even="test")