@Override
@Test
default void Bag_occurrencesOf() {
SortedBag<Integer> bag = this.newWith(3, 3, 3, 2, 2, 1);
assertEquals(0, bag.occurrencesOf(0));
assertEquals(1, bag.occurrencesOf(1));
assertEquals(2, bag.occurrencesOf(2));
assertEquals(3, bag.occurrencesOf(3));
}
