Enabling focus on pie chart graph error (canBecomeFocused)

Hello,

I'm building an app for tvOS.
I have a view controller with few graphs. I made them focusable by extending the classes:

`extension BarChartView{
override open var canBecomeFocused: Bool{
return true
}
}
extension HorizontalBarChartView{
override open var canBecomeFocused: Bool{
return true
}
}
extension PieChartView{
override open var canBecomeFocused: Bool{
return true
}
}
extension LineChartView{
override open var canBecomeFocused: Bool{
return true
}
}`

Once I focus on the PieChartView I get the following errors running repeatedly (and the graph gets broken):

Jan 18 12:03:51 ***[1014] : If you want to see the backtrace, please set CG_NUMERICS_SHOW_BACKTRACE environmental variable.
2017-01-18 12:03:51.809137 ***[1014:595773] Error: this application, or a library it uses, has passed an invalid numeric value (NaN, or not-a-number) to CoreGraphics API and this value is being ignored. Please fix this problem.

Dear graph masters - please advice what to do...