I want stacked bars, got zebra instead

[Pitel]

chart.setHardwareAccelerationEnabled(true)
chart.setTouchEnabled(false)
chart.description = null
chart.legend.isEnabled = false
chart.axisLeft.isEnabled = false
//chart.axisLeft.axisMinimum = 0.toFloat()
chart.axisLeft.axisMaximum = 120.toFloat()
chart.axisRight.isEnabled = false
chart.xAxis.isEnabled = false
chart.setDrawGridBackground(false)
chart.data = BarData()
chart.data.setDrawValues(false)
val dataSet = BarDataSet(mutableListOf(), null)
dataSet.setColors(intArrayOf(R.color.colorPrimary, R.color.colorAccent), this) // Colors
dataSet.setDrawValues(false)
chart.data.addDataSet(dataSet)

// This simulates how realtime data will be added later
chart.data.addEntry(BarEntry(chart.data.dataSets.first().entryCount.toFloat(), floatArrayOf(0.toFloat(), 20.toFloat())), 0)
chart.data.addEntry(BarEntry(chart.data.dataSets.first().entryCount.toFloat(), floatArrayOf(30.toFloat(), 20.toFloat())), 0)
chart.data.addEntry(BarEntry(chart.data.dataSets.first().entryCount.toFloat(), floatArrayOf(60.toFloat(), 20.toFloat())), 0)
chart.data.addEntry(BarEntry(chart.data.dataSets.first().entryCount.toFloat(), floatArrayOf(90.toFloat(), 20.toFloat())), 0)
chart.data.addEntry(BarEntry(chart.data.dataSets.first().entryCount.toFloat(), floatArrayOf(120.toFloat(), 20.toFloat())), 0)

I expect to get colored stacked bars, but instead, I get this:

What am I doing wrong? I'm setting colors to dataset, I'm using array for yVal in BarEntry, and it worked fine in previous project. Only difference is, this new project is in Kotlin.

[Pitel]

Solution: DataSet must be einitalized with stacked BarEntry

val dataSet = BarDataSet(mutableListOf(BarEntry(0.toFloat(), floatArrayOf(0.toFloat(), 0.toFloat()))), null)

I can't find this in documentation anywhere. Maybe it should be.