Multiset<String> toRemove = HashMultiset.create(asList("a", "b", "a"));
    assertFalse(Multisets.removeOccurrences(multiset, toRemove));
    assertTrue(multiset.isEmpty());
  }

  public void testUnion() {
    Multiset<String> ms1 = HashMultiset.create(asList("a", "b", "a"));
    Multiset<String> ms2 = HashMultiset.create(asList("a", "b", "b", "c"));
    assertThat(union(ms1, ms2)).containsExactly("a", "a", "b", "b", "c");

          .add(Range.openClosed(0, 3))
          .add(Range.closed(5, 8))
          .add(Range.closedOpen(12, 15))
          .add(Range.open(19, 20))
          .build();

  public void testUnion() {
    RangeSet<Integer> expected =
        ImmutableRangeSet.<Integer>builder()
            .add(Range.openClosed(0, 4))
            .add(Range.closedOpen(5, 10))
            .add(Range.closedOpen(12, 15))