def gensquares(r):
for i in range(r):
yield i
a = gensquares(5)
print(next(gensquares(5)))
print(next(a))
print(next(gensquares(5)))
print(next(a))
print(next(gensquares(5)))
print(next(a))
print(next(gensquares(5)))
print(next(a))
为什么 next(gensquares(5) 不进行迭代?