jquery - add class to dots, after activated it with delay and remove that class after slider cycle over -

i need add class dots, after activated delay , remove class after slider cycle over. using slick slider

if ( $('.slick-dots li').hasclass('slick-active') ) {     $(".slick-dots li.slick-active button").addclass("bg-b").delay(3000);    } 

can 1 me?