class Fib(object):

    def __init__(self, num):
        a=0
        b=1
        L=[]
        for n in range(num):
            L.append(a)
            a=b
            b=a+b#这里这么写为什么会输出错误- -
            self.numbers=L
    def __str__(self):
        return str(self.numbers)

    __repr__=__str__
    def __len__(self):
        return len(self.numbers)

f = Fib(10)
print f
print len(f)