docs: public static final <T extends Comparable<T>> int comparator(T val1, T def1, T val2, T def2) {
  		return comparator(val1 == null? def1 : val1, val2 == null? def2 : val2);
  		// return (val1 == null? def1 : val1).compareTo(val2 == null? def2 : val2);
  	}