Sidemenu with child menu

hey all! could anyone please explain or give some example for adding a childmenu in sidemenu in ionic v1. like if i clicked in the (parent) inventory, it should display the (child) product & variant below the inventory menu. i created the project in the ionic v1 with sidemenu template. Thanks!

You can create a collapsible list inside side menu. examples are given on various sites sharing some links for reference