How to use the sprotty/lib.isSelectable function in sprotty

export function isResizeable(element: SModelElement): element is SParentElement & BoundsAware {
    return element.hasFeature(resizeFeature) && isBoundsAware(element) && isSelectable(element) && element instanceof SParentElement;
}

export function isResizable(element: SModelElement): element is SParentElement & Resizable {
    return isBoundsAware(element) && isSelectable(element) && element instanceof SParentElement && element.hasFeature(resizeFeature);
}

export function isSelected(element: SModelElement | undefined): element is SModelElement & Selectable {
    return isNotUndefined(element) && isSelectable(element) && element.selected;
}

            const deleteElementIds = Array.from(element.root.index.all().filter(e => isDeletable(e) && isSelectable(e) && e.selected)
                .filter(e => e.id !== e.root.id).map(e => e.id));

                .filter(element => isSelectable(element) && element.selected)
                .forEach(element => {

            const selected = toArray(element.root.index.all().filter(e => isSelectable(e) && e.selected)).map(e => e.id);
            return [new ShowDiagramUIExtensionAction(CommandPalette.ID, selected)];