Deive signed a contract for membership in a physical fitness program. The contract provided that he was obligated to make payments whether he participated in the program or not. Deive had a lung ailment when he signed the contract but never mentioned it to the operators of the program. After he had signed the contract, Deive’s doctor told him that participation in the program would be dangerous to his health. Deive tried to cancel the contract and refused to pay his fees. The plaintiff sued for breach of contract. Can Deive cancel the contract based on impossibility of performance?