13.5 In this exercise, we will add nondeterminism to the environment from Exercise 13.4.

a. Modify your environment so that with probability 0.1, an action fails—that is, one of the effects does not occur. Show an example of a plan not working because of an action failure.

b. Modify your planning agent to include a simple replanning capability. It should call POP to construct a repair plan to get back to the desired state along the solution path, execute the repair plan (calling itself recursively, of course, if the repair plan fails), and then continue executing the original plan from there. (You may wish to start by having failed actions do nothing at all, so that this recursive repair method automatically results in a

"loop-until-success" behavior; this will probably be easier to debug!)

c. Show that your agent can fix the tire in this new environment.