ActionScript: duplicate getter/setter generation available with alt-insert

I have already generated getters and setters for firstName and lastName fields.

When I press alt-insert I see the list suggesting me to generate firstName and lastName besides age.

package  obj {
public class Person {
    private var firstName:String;
     private var lastName:String;
    private var age:int;

    public function Person() {
    }

    public  function get firstName():String {
        return firstName;
    }

    public  function set firstName(value:String):void {
        firstName =  value;
    }

    public function get lastName():String {
         return lastName;
    }

    public function set  lastName(value:String):void {
        lastName = value;
    }
}
}