As the code show，the name of event should be same as @output property which is ”lastPrice“，but in following bold string ：
“On the application level, the event handler for the last-price event is invoked to display the price quote that arrives with the event object”
The event which is named "lastPrice" is called "last-price" wrongly
As the code show，the name of event should be same as @output property which is ”lastPrice“，but in following bold string ：
“On the application level, the event handler for the last-price event is invoked to display the price quote that arrives with the event object”
The event which is named "lastPrice" is called "last-price" wrongly