//------------------------------------------------------------------------------------------------
public static Frame<string, string> sortFrameByNaturalOrder(Frame<string, string> input, List<string>contractSortOrder )
//------------------------------------------------------------------------------------------------
{
var series = input.GetColumn<string>("ticker").SelectValues(s => futuresSortValue(s, contractSortOrder));
input.AddColumn("SortValue",series);
input = input.SortRows("SortValue");
return input;
}