 
     private let groups: [ChartPointsBarGroup<T>]
     
+    private let barWidth: CGFloat?
     private let barSpacing: CGFloat?
     private let groupSpacing: CGFloat?
     


public typealias ChartGroupedPlainBarsLayer = ChartGroupedPlainBarsLayer_<Any>
public class ChartGroupedPlainBarsLayer_<N>: ChartGroupedBarsLayer<ChartBarModel> {

    public override init(xAxis: ChartAxis, yAxis: ChartAxis, groups: [ChartPointsBarGroup<ChartBarModel>], horizontal: Bool, barSpacing: CGFloat?, groupSpacing: CGFloat?, animDuration: Float) {
        super.init(xAxis: xAxis, yAxis: yAxis, groups: groups, horizontal: horizontal, barSpacing: barSpacing, groupSpacing: groupSpacing, animDuration: animDuration)
    }
    
    override func barsGenerator(barWidth barWidth: CGFloat, chart: Chart) -> ChartBarsViewGenerator<ChartBarModel> {


    private var barViews: [UIView] = []
    
    convenience init(xAxis: ChartAxis, yAxis: ChartAxis, groups: [ChartPointsBarGroup<T>], horizontal: Bool = false, barSpacing: CGFloat?, groupSpacing: CGFloat?, animDuration: Float) {
        self.init(xAxis: xAxis, yAxis: yAxis, groups: groups, horizontal: horizontal, barWidth: nil, barSpacing: barSpacing, groupSpacing: groupSpacing, animDuration: animDuration)
    }
    
    init(xAxis: ChartAxis, yAxis: ChartAxis, groups: [ChartPointsBarGroup<T>], horizontal: Bool = false, barWidth: CGFloat?, barSpacing: CGFloat?, groupSpacing: CGFloat?, animDuration: Float) {
        self.groups = groups
        self.horizontal = horizontal
        self.barWidth = barWidth
        self.barSpacing = barSpacing
        self.groupSpacing = groupSpacing
        self.animDuration = animDuration
