The function makeBrandPair creates two associated objects, a sealer and an unsealer, such that the sealer can seal an object in a box and the unsealer is the only object that can retrieve the contents of the box.
函数makeBrandPair创建了两个关联对象，一个sealer和一个unsealer，这样sealer就可以在一个盒子中封口一个对象，而unsealer就是唯一可以检索盒子中内容的对象。