How to set multiple Stackbar with Charts 3

[PreechaS]

#1801 I can't figure out how to do it in Charts 3.
It used to work well with the previous version of iOS-charts.(swift 2)

This is sample code and output so you may can tell me what is wrong.

    for i in 0..<12 {
        let value = Double(i)
        let attempt = BarChartDataEntry(x: value, y: value)
        attemptEntries.append(attempt)
        let result = BarChartDataEntry(x: value, yValues: [2*value, 3*value])
        resultEntries.append(result)
    }
    let attemptDataSet = BarChartDataSet(values: attemptEntries, label: Constants.Chart.TotalAttempt.Label)
    let resultDataSet = BarChartDataSet(values: resultEntries, label: Constants.Chart.Result.Label)

    let dataSets = [attemptDataSet, resultDataSet]
    let barData = BarChartData(dataSets: dataSets)

    chartView.data = barData

[liuxuan30]

Dup. #1801
Don't create dup issue. we will update if needed