a!pieChartField(
              label: " Organization Code :  Number of Letters ",
              series: apply(
                rule!GetPieChartSeries(
                  label: _,
                  data: _,
                  saveInto: local!selectedCode << fn!append(
                    _,
                    "_2"
                  )
                ),
                merge(
                  local!data.label,
                  local!data.data
                )
              ),
              showDataLabels: true,
              showTooltips: true
            )
------------------------------------------------------------------------------------

GetPieChartSeries defined as below : 

=a!chartSeries(
  label: ri!label,
  data: ri!data,
  links: a!dynamicLink(value: ri!label, saveInto:ri!saveInto)
)