- can now safely use labelList::null() instead of emptyLabelList for
return values. No special treatment required for lists.
if (notNull(list) && list.size()) -> if (list.size())
if (isNull(list) || list.empty()) -> if (list.empty())
The receiver may still wish to handle differently to distinguish
between a null list and an empty list, but no additional special
protection is required when obtaining sizes, traversing, outputting