The first parameter is the Notification object which was emitted, and the second is the handback, an opaque object which can be used if some sort of context is needed.
第一个参数是被发出的Notification对象，第二个则是handback，一个不透明的对象，如果需要某种上下文的话，它就会被用到。
As in entering a walled enclosure, the building looks permeable from the interior and opaque from its urban context.
当进入由墙围合起的这片区域时，建筑的室内与室外互相渗透，但对于外部的城市环境却是不透明的。
As in entering a walled enclosure, the building looks permeable from the interior and opaque from its urban context.
当进入由墙围合起的这片区域时，建筑的室内与室外互相渗透，但对于外部的城市环境却是不透明的。
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