A defendant ordered from the plaintiff two lead$-$covered steel tanks to be constructed by the plaintiff according to specifications supplied by the defendant. The tanks were designed for the special purpose of testing $x-$ray tubes and were required to be radiation$-$proof within certain federal standards. The defendant inspected the goods and accepted them, notwithstanding some defects. The defendant then attempted to revoke the acceptance but did not do so properly. The plaintiff retained possession of the tanks; when the defendant failed to pay for them, suit was filed for the purchase price. Is the plaintiff entitled to the purchase price? Explain.