return new FilteredSortedSet<>(((SortedSet<E>) unfiltered).headSet(toElement), predicate);
    }

    @Override
    public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
      return new FilteredSortedSet<>(((SortedSet<E>) unfiltered).tailSet(fromElement), predicate);
    }

    @Override
    @ParametricNullness
    public E first() {

      return new FilteredSortedSet<>(((SortedSet<E>) unfiltered).headSet(toElement), predicate);
    }

    @Override
    public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
      return new FilteredSortedSet<>(((SortedSet<E>) unfiltered).tailSet(fromElement), predicate);
    }

    @Override
    @ParametricNullness
    public E first() {

    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      synchronized (mutex) {
        return Synchronized.navigableSet(delegate().tailSet(fromElement, inclusive), mutex);
      }
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {
      return tailSet(fromElement, true);
    }

    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      synchronized (mutex) {
        return Synchronized.navigableSet(delegate().tailSet(fromElement, inclusive), mutex);
      }
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {
      return tailSet(fromElement, true);
    }

    ensureNotDirectlyModifiable(unmod.headSet(2));
    ensureNotDirectlyModifiable(unmod.headSet(2, true));
    ensureNotDirectlyModifiable(unmod.tailSet(2));
    ensureNotDirectlyModifiable(unmod.tailSet(2, true));
    ensureNotDirectlyModifiable(unmod.subSet(1, 3));
    ensureNotDirectlyModifiable(unmod.subSet(1, true, 3, true));

				},
				Transition: Transition{
					Days:         TransitionDays(3),
					StorageClass: "TIER-1",
				},
			},
			{
				ID:     "rule-2",
				Status: "Enabled",
				Filter: Filter{
					tagSet: true,
					Tag: Tag{
						Key:   "priority",
						Value: "low",
					},
				},
				Transition: Transition{
					Days:         TransitionDays(3),
					StorageClass: "TIER-2",
				},

		Description:    "Bucket is missing ObjectLockConfiguration",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrBucketTaggingNotFound: {
		Code:           "NoSuchTagSet",
		Description:    "The TagSet does not exist",
		HTTPStatusCode: http.StatusNotFound,
	},
	ErrObjectLockConfigurationNotFound: {
		Code:           "ObjectLockConfigurationNotFoundError",