return oc;
}
private void initialize() {
list_of_comparators.add(new LeafStringComparator());
list_of_comparators.add(new LeafIntegerComparator());
list_of_comparators.add(new LeafDoubleComparator());
list_of_comparators.add(new LeafBooleanComparator());
list_of_comparators.add(new IterableComparator());
default_comparator = new FieldBasedComparator();
}