evel side navigation
    [].forEach.call(document.querySelectorAll(".docs-navigation .nav-dropdown"), function registerSideNavActions(collapsibleElement) {
        collapsibleElement.addEventListener("click", function toggleExpandedSideNav(evt) {
            evt.preventDefault();
            evt.target.classList.toggle("expanded");
            evt.target.setAttribute("aria-expanded", evt.target.classList.contains("expanded").toString());
            return false;
        }, false);
    });

    function pos