def learn_yield():
print("1")
yield 1
print("2")
yield 2
print("3")
yield 3
yield 6
yield 1
print("4")
learn_yield().__next__()
learn_yield().__next__()
learn_yield().__next__()
learn_yield().__next__()
a=learn_yield()
a.__next__()
a.__next__()
a.__next__()
a.__next__()
a.__next__()
learn_yield().__next__()
函数后面的执行代码可以一条条加着去运行
