         return cptFormatter
     }
 
-    class func rangeScale(_ range: CPTPlotRange?) -> RangeScale {
+    class func rangeScale(range: CPTPlotRange?) -> RangeScale {
 
         guard let axisRange = range else {
             return .month

                + (0.1 * range.lengthDouble)))
            axisSet.xAxis?.labelFormatter = xLabelFormatter(range: range)

        } else if (coordinate == CPTCoordinate.Y) && (trend != nil) {

            // keep original range, don't change to newRange

        // e.g. "Dec 5, 2016"
        //dateFormatter.dateStyle = .medium
        // e.g. "12/05"
        let rangeScale = TrendViewController.rangeScale(range: range)
        let templateString = templateStringForRangeScale(rangeScale)
        let formatString = DateFormatter.dateFormat(fromTemplate: templateString,
                                                    options:0, locale:NSLocale.current)
