* @param {Array.<Array.<(?number|Array<?number>)>} series Array where
* series[row] = [x,y] or [x, [y, err]] or [x, [y, yplus, yminus]].
* @param {boolean} bars True if error bars or custom bars are being drawn.
* @param {Array.<Array.<(?number|Array<?number>)>} series Array where
* series[row] = [x,y] or [x, [y, err]] or [x, [y, yplus, yminus]].
* @param {boolean} bars True if error bars or custom bars are being drawn.