add(id) {
        this._node.children.push({
            name: "brk",
            children: [],
            attributes: {
                id,
                max: 16383,
                man: 1
            }
        });
        this._node.attributes.count++;
        this._node.attributes.manualBreakCount++;

        return this;
    }
add page-breaks by row/column id
@param {number} id - row/column id (rowNumber/colNumber)
@return {PageBreaks} the page-breaks