in src/topic/tree/TopicTreeItem.ts [25:34]
public constructor(parent: TopicProvider, topic: Topic) {
super(parent);
if (!topic.id || !topic.name) {
throw new ArgumentError(topic);
}
this.id = topic.id;
this._name = topic.name;
this._resourceGroup = azureUtils.getResourceGroupFromId(topic.id);
}