     func takeOwnershipOfAsset(asset: Asset) {
         asset.owner = self
         assets.append(asset)
+        accountant.gainedNewAsset(asset)
+    }
+    
+    func netWorthDidChange(netWorth: Double) {
+        print("The net worth of \(self) is now \(netWorth)")
     }
 }

class Person: CustomStringConvertible {
    let name: String
    var assets = [Asset]()
    
    var description: String {

    
    init(name: String) {
        self.name = name
        accountant.netWorthChangedHandler = {
            netWorth in
            self.netWorthDidChange(netWorth)
            return
        }
    }
    
    deinit {
