פירוש על קידושין 120:5

In this baraita, the man again makes the divorce dependent on her giving him 200 zuz. He then dies. If she gave the money she is a divorcee and not liable for yibbum. But if she did not give the money, she is a widow. According to the first opinion, she cannot give it to his heirs. According to R. Shimon b. Gamaliel she can give it to his heirs. Tje only dispute is about whether she can give the money to the heirs. All would hold that she is divorced immediately as long as at some point she gives the money (according to the first opinion, she simply will never have such an opportunity). Thus this is again a difficulty against R. Yehudah.