def fib(count):
n,before, after = 0,0,1
for i in range(count):
before, after = after, before+after
yield before#替代了print(before)
g = fib(8)
print(g)
print(g.__next__())
print(next(g))
print(next(g))
print(next(g))
print(next(g))
print(next(g))
print(next(g))