Component nesting in DevExtreme jquery

Help, please, I study DevExpress and I cannot understand something. How can I nest components? For example, so that dxAccordion in one of the items contains one more dxAccordion. I've seen it written like this: widget: 'dxAccordion' and then the nested component will become the accordion when the parent is rendered. But it doesn't work. It should look something like this:

const items = [
    {widget:'dxButton', options:{text:'Button'}},
    {widget:'dxCalendar', options:{firstDayOfWeek:1}}
];

$('dx-acc').dxAccordion({
    dataSource: items
})

And I would like the button and calendar to be automatically added to the accordion