anchor.diff:      group('removing', () {
         test('zero', () {
           final set = Multiset.of(['a', 'a', 'b', 'b', 'b']);
  -        set..remove('a', 0)..remove('b', 0);
  +        set
  +          ..remove('a', 0)
  +          ..remove('b', 0);
           expect(set, isNot(isEmpty));
           expect(set, hasLength(5));
           expect(set, unorderedEquals(['a', 'a', 'b', 'b', 'b']));
  
positive.code:         expect(set.counts, unorderedEquals([1, 2]));
        });
        test('multiple', () {
          final set = Multiset()..add('a', 2)..add('b', 3);
          expect(set, isNot(isEmpty));
          expect(set, hasLength(5));
          expect(set, unorderedEquals(['a', 'a', 'b', 'b', 'b']));
  
negative.code:       });
        test('multiple', () {
          final set = Multiset.of(['a', 'a', 'b', 'b', 'b']);
          set
            ..remove('a', 3)
            ..remove('b', 2);
          expect(set, isNot(isEmpty));
          expect(set, hasLength(1));
          expect(set, unorderedEquals(['b']));
  