return asList(data.toArray(new String[data.size()]));
}
public static Collection<Integer> create(IntegerList aList) {
List<Integer> data = new ArrayList<Integer>();
IntegerList i = aList;
while (i instanceof NonEmptyIntegerList) {
NonEmptyIntegerList l = (NonEmptyIntegerList) i;
data.add(l.getHead());
i = l.getTail();
}