class ADuck
    def quack()
        puts "quack A";
    end
end
class BDuck
    def quack()
        puts "quack B";
    end
end
# quack_it doesn't care about the type of the argument duck, as long
# as it has a method called quack. Classes A and B have no
# inheritance relationship.
def quack_it(duck)
    duck.quack
end
a = ADuck.new
b = BDuck.new
quack_it(a)
quack_it(b)

xmlPersistence xmlPersistence
 = (XMLPersistence)persistenceManager.getPersistence();

xmlPersistence = persistence_manager.persistence.