Gradescale Rangemap
@Test
public void google_guava_range_map_example () {
RangeMap<Integer, String> gradeScale = TreeRangeMap.create();
gradeScale.put(Range.closed(0, 60), "F");
gradeScale.put(Range.closed(61, 70), "D");
gradeScale.put(Range.closed(71, 80), "C");
gradeScale.put(Range.closed(81, 90), "B");
gradeScale.put(Range.closed(91, 100), "A");
String grade = gradeScale.get(77);
assertEquals("C", grade);
}