topic
The area of study to which a context relates.
Declaration
var topic: CLSContextTopic? { get set }Discussion
Set the topic to tell teachers what kind of content a given context covers using one of the values from CLSContextTopic. The topic set on a context applies to that context and any of its descendants for which you haven’t explicitly set a topic. If your entire app covers only a single topic, you only need to set the topic for the mainAppContext.