You enter into a contract with a friend to mow and water her lawn from April 1 until November 1. Your friend pays you in advance for the entire contract at the rate of $500 per month. On July 1, in response to a severe drought, your friend's town has banned the mowing and watering of lawns until December 1.

What is the effect of the town's ban on the contract between you and your friend? Please explain your answer.

On July 2nd, your friend asks you for the money back for the months you can no longer mow and water her lawn, but you can't because you used it to purchase a new lawn mower. She sues you. Judgment for whom? Please explain.