生产者消费：

1 def consumer(name): 2     print("我是%s,我准备吃包子！" %name) 3     while True: 4         baozi = yield 5         print("%s 很开心的把【%s】吃掉了" %(name,baozi)) 6  7 def producer(): 8     c = consumer("alex") 9     c1 = consumer("tom")10     next(c)11     next(c1)12     for i in range(10):13         if i / 2 ==0:14             c.send("包子%s" %i)15         else:16             c1.send("包子%s" %i)17 producer()