def Afunction(f):
    def w(self, *x, **y):
        self.whatever = 1
        f(self, *x, **y)
    return w
def Bfunction(f):
    def w(self, *x, **y):
        self.whatever = 1
        f(self, *x, **y)
    return w
class C(object):
    @Afunction
    @Bfunction
    def __init__(self):
       ....