freezePanes() {
        return new ArgHandler('Sheet.feezePanes')
            .case(['integer', 'integer'], (xSplit, ySplit) => {
                const topLeftCell = addressConverter.columnNumberToName(xSplit + 1) + (ySplit + 1);
                let activePane = xSplit === 0 ? 'bottomLeft' : 'bottomRight';
                activePane = ySplit === 0 ? 'topRight' : activePane;
                return this.panes({ state: 'frozen', topLeftCell, xSplit, ySplit, activePane });
            })
            .case(['string'], topLeftCell => {
                const ref = addressConverter.fromAddress(topLeftCell);
                const xSplit = ref.columnNumber - 1, ySplit = ref.rowNumber - 1;
                let activePane = xSplit === 0 ? 'bottomLeft' : 'bottomRight';
                activePane = ySplit === 0 ? 'topRight' : activePane;
                return this.panes({ state: 'frozen', topLeftCell, xSplit, ySplit, activePane });
            })
            .handle(arguments);
    }
freezes Panes for this sheet.
@param {string} topLeftCell Top Left Visible Cell. Location of the top left visible cell in the bottom
right pane (when in Left-To-Right mode).
@return {Sheet} The sheet