activeCell() {
        const sheetViewNode = this._getOrCreateSheetViewNode();
        let selectionNode = xmlq.findChild(sheetViewNode, "selection");
        return new ArgHandler('Sheet.activeCell')
            .case(() => {
                const cellAddress = selectionNode ? selectionNode.attributes.activeCell : "A1";
                return this.cell(cellAddress);
            })
            .case(['number', '*'], (rowNumber, columnNameOrNumber) => {
                const cell = this.cell(rowNumber, columnNameOrNumber);
                return this.activeCell(cell);
            })
            .case('*', cell => {
                if (!selectionNode) {
                    selectionNode = {
                        name: "selection",
                        attributes: {},
                        children: []
                    };

                    xmlq.appendChild(sheetViewNode, selectionNode);
                }

                if (!(cell instanceof Cell)) cell = this.cell(cell);
                selectionNode.attributes.activeCell = selectionNode.attributes.sqref = cell.address();
                return this;
            })
            .handle(arguments);
    }
Set the active cell in the workbook by row and column.
@param {number} rowNumber - The row number of the cell.
@param {string|number} columnNameOrNumber - The column name or number of the cell.
@returns {Sheet} The sheet.