sortedUniqBy function
Implementation
List sortedUniqBy(List list, Function iteratee) {
List result = [];
for (int i = 0; i < list.length; i++) {
if (i == 0 || !isEqual(iteratee(list[i]), iteratee(list[i - 1]))) {
result.add(list[i]);
}
}
return result;
}