public object ProcessingBoundary(IList<SummaryCellData> columnCellsSummaryData)
{
if (columnCellsSummaryData == null || !columnCellsSummaryData.Any()) return 0;
var list = columnCellsSummaryData;
var count = list.Count();
var sum = list.Sum(item => Convert.ToDouble(item.CellData.PropertyValue, CultureInfo.InvariantCulture));
return sum / count;
}