ConstDecorator for adding sublists with each line of the sublist represented by a type T which defines the properties you want on the sublist
Constructor for the type that has the properties you want from each sublist line. e.g. Invoice.ItemSublistLine
this isn't a native NS 'field' type, but rather is used to indicate a property should represent a NS sub-list. Pass a type derived from SublistLine that describes the sublist fields you want. e.g. Invoice.ItemSublistLine