The city has a set of by-laws that control the availability and operation of taxi cabs. To be a taxi driver, a person must hold both (i) a special driver's licence and (ii) a special permit for their vehicle. The driver's licence is relatively easy to acquire. A person must simply pay a fee and pass a series of examinations. The vehicle permit, in contrast, is very difficult to obtain. The by-laws strictly limit the number of permits that exist at any time. The city occasionally increases that number, but there is always a long waiting list (usually about four years in length) for anyone wishing to purchase a new permit. There is only one other option for a person who hopes to begin operating a taxi. A driver who already owns a permit is entitled to sell it privately. That situation, however, occurs only rarely, and when it does, there is always a huge demand. Rich McTiernan recently decided to retire after driving a taxi for more than 30 years. After considering several offers, he contractually agreed to sell the permit to William Dixon for $50 000. Dixon immediately paid a deposit of $5000 and the parties agreed that the sale would be completed at the end of the year. In early December, however, McTiernan learned that, as a result of a recent turn in the stock market, his pension was worth much less than he had believed. He therefore decided that he would need to continue driving his taxi for five or ten years. He then told Dixon that the sale would have to be called off. Dixon is furious. He insists that McTiernan is required to complete the sale by handing over the vehicle permit in exchange for the agreed price. What result would a court most likely reach? Explain your answer.