excludedSize (excludedSize) {
        if (!arguments.length) {
            return this._excludedSize;
        }
        this._excludedSize = excludedSize;
        return this;
    }
Set or get size for symbols excluded from this chart's filter. If null, no
special size is applied for symbols based on their filter status.
@see {@link https://github.com/d3/d3-shape/blob/master/README.md#symbol_size d3.symbol.size}
@param {Number} [excludedSize=null]
@returns {Number|ScatterPlot}