A publisher entered into a contract with a paper manufacturer who used very fine materials, whereby the publisher was given the right to purchase all paper refined by the paper manufacturer for the next five years at a price set at 95% of the domestic market price at the time of delivery. The publisher agreed to purchase no less than 1,000 pounds of paper a week. At the time this contract was signed, the publisher gave written notice to the paper manufacturer that it intended to buy all paper produced by the paper manufacturer until further notice. The paper manufacturer then sold its business to a lumber-processing company. What is the effect of this sale on the paper manufacturer's obligation to the publisher?