I don't speak English well.

CombinedChartView.initialize() -> () (CombinedChartView.swift:40)
CombinedChartView.initialize() -> () (CombinedChartView.swift:40)
ChartViewBase.init(frame : CGRect) -> ChartViewBase (ChartViewBase.swift:145)
BarLineChartViewBase.init(frame : CGRect) -> BarLineChartViewBase (BarLineChartViewBase.swift:75)
@objc CombinedChartView.init(frame : CGRect) -> CombinedChartView (CombinedChartView.swift:0)
-PDNoteBMIChangeWeightDetailView setupChartView

I found suspicious part in BarLineChartFillFormatter : 1650

private weak var _chart: BarLineChartViewBase!

I erased the 'weak'. so it's not crash anymore.
What right have I modified the way?