code: function (brushOption) {
          if (__DEV__) {
              zrUtil.assert(this._mounted);
          }
  
          this._brushType && doDisableBrush(this);
          brushOption.brushType && doEnableBrush(this, brushOption);
  
          return this;
      }
docs: If set to null/undefined/false, select disabled.
  @param {Object} brushOption
  @param {string|boolean} brushOption.brushType 'line', 'rect', 'polygon' or false
  If passing false/null/undefined, disable brush.
  If passing 'auto', determined by panel.defaultBrushType.
  ('auto' can not be used in global panel)
  @param {number} [brushOption.brushMode='single'] 'single' or 'multiple'
  @param {boolean} [brushOption.transformable=true]
  @param {boolean} [brushOption.removeOnClick=false]
  @param {Object} [brushOption.brushStyle]
  @param {number} [brushOption.brushStyle.width]
  @param {number} [brushOption.brushStyle.lineWidth]
  @param {string} [brushOption.brushStyle.stroke]
  @param {string} [brushOption.brushStyle.fill]
  @param {number} [brushOption.z]