class?Fib(object):

????def?__init__(self,?num):
????????self.num=num
????
????def?__str__(self):
????????self.a=list(reduce(lambda?x:x+x,list(range(0,self.num))))
????????return?self.a
????

????def?__len__(self):
????????return?len(self.a)

f?=?Fib(10)
print?f
print?len(f)
無法執行成功，應該改哪里呢？