Accordion: How to code for: when expanding 1 item, collapse others?

[pasionmichael]

$w.onReady(function () {

    $w('#repeater1').forEachItem(( $item ) => {
        $item('#contentTrigger').onClick(() => {
 if ($item('#contentContainer').collapsed)
                $item('#contentContainer').expand();
 else
                $item('#contentContainer').collapse();
 })
 }) 
 
});