def go():
  while True:
    data = 1
    r = yield data # data是返回值，r是接收值
    print("data", data)
    print("A1", r)
    data += 1

    r = yield data
    print("data",data)
    r += r
    print("A2", r)
    data += 1

    r = yield data
    print("data",data)
    print("A3", r)
    # 运行时此后若找不到下一个yield，则会报错StopIteration

my = go()
print("my", my)
print("None", my.send(None))
print(my.send("1"))
print(my.send("2"))
print(my.send("3"))