crash dump GetValues(...)

[BudzikM]

panic: runtime error: index out of range [0] with length 0

github.com/wcharczuk/go-chart/v2.TimeSeries.GetValues(...)
/home/budzik/go/pkg/mod/github.com/wcharczuk/go-chart/[email protected]/time_series.go:45
github.com/wcharczuk/go-chart/v2.Chart.getRanges({{0x71c367, 0x14}, {0x0, {0x0, 0x0, 0x0, 0x0, 0x0}, {0x0, 0x0}, ...}, ...})
/home/budzik/go/pkg/mod/github.com/wcharczuk/go-chart/[email protected]/chart.go:210 +0xd07
github.com/wcharczuk/go-chart/v2.Chart.Render({{0x71c367, 0x14}, {0x0, {0x0, 0x0, 0x0, 0x0, 0x0}, {0x0, 0x0}, ...}, ...}, ...)
/home/budzik/go/pkg/mod/github.com/wcharczuk/go-chart/[email protected]/chart.go:102 +0x23f
server_app/energy.GenerateCharts()