x (scale) {
        if (!arguments.length) {
            return this._x;
        }
        this._x = scale;
        return this;
    }
Gets or sets the x scale. The x scale can be any d3
{@link https://github.com/d3/d3-scale/blob/master/README.md d3.scale}.
@see {@link https://github.com/d3/d3-scale/blob/master/README.md d3.scale}
@param {d3.scale} [scale]
@returns {d3.scale|RowChart}