How to use the @fullcalendar/daygrid.DayBgRow function in @fullcalendar/daygrid

TimeGrid.prototype._renderColumns = function (cells, dateProfile) {
        var _a = this, theme = _a.theme, dateEnv = _a.dateEnv, view = _a.view;
        var bgRow = new DayBgRow(this.context);
        this.rootBgContainerEl.innerHTML =
            '' +
                bgRow.renderHtml({
                    cells: cells,
                    dateProfile: dateProfile,
                    renderIntroHtml: this.renderProps.renderBgIntroHtml
                }) +
                '<table class="' + theme.getClass('tableGrid') + '"></table>';
        this.colEls = findElements(this.el, '.fc-day, .fc-disabled-day');
        for (var col = 0; col &lt; this.colCnt; col++) {
            this.publiclyTrigger('dayRender', [
                {
                    date: dateEnv.toDate(cells[col].date),
                    el: this.colEls[col],
                    view: view
                }

_renderColumns(cells: TimeGridCell[], dateProfile: DateProfile) {
    let { calendar, view, isRtl, theme, dateEnv } = this.context

    let bgRow = new DayBgRow(this.context)
    this.rootBgContainerEl.innerHTML =
      '' +
        bgRow.renderHtml({
          cells,
          dateProfile,
          renderIntroHtml: this.renderProps.renderBgIntroHtml
        }) +
      '<table class="' + theme.getClass('tableGrid') + '"></table>'

    this.colEls = findElements(this.el, '.fc-day, .fc-disabled-day')

    for (let col = 0; col &lt; this.colCnt; col++) {
      calendar.publiclyTrigger('dayRender', [
        {
          date: dateEnv.toDate(cells[col].date),
          el: this.colEls[col],