}

      @Override
      public boolean contains(@CheckForNull Object element) {
        return set1.contains(element) && !set2.contains(element);
      }
    };
  }

  /**
   * Returns an unmodifiable <b>view</b> of the symmetric difference of two sets. The returned set
   * contains all elements that are contained in either {@code set1} or {@code set2} but not in

    while (removeFrom.hasNext()) {
      if (!elementsToRetain.contains(removeFrom.next())) {
        removeFrom.remove();
        result = true;
      }
    }
    return result;
  }

  /**
   * Determines whether two iterators contain equal elements in the same order. More specifically,
   * this method returns {@code true} if {@code iterator1} and {@code iterator2} contain the same

      }

      @Override
      public boolean remove(@CheckForNull Object o) {
        if (!contains(o)) {
          return false;
        }
        // requireNonNull is safe because of the contains check.
        Map.Entry<?, ?> entry = requireNonNull((Map.Entry<?, ?>) o);
        removeValuesForKey(entry.getKey());
        return true;
      }
    }

   * keys and values are the result of applying the provided mapping functions to the input
   * elements. The generated map is sorted by the specified comparator.
   *
   * <p>If the mapped keys contain duplicates (according to the specified comparator), an {@code
   * IllegalArgumentException} is thrown when the collection operation is performed. (This differs

					cache.iamUserPolicyMap.Delete(u)
					return true
				}
			}
			if pset.Contains(policy) {
				users = append(users, u)
			}
			return true
		})
		cache.iamGroupPolicyMap.Range(func(g string, mp MappedPolicy) bool {
			pset := mp.policySet()
			if pset.Contains(policy) {
				groups = append(groups, g)
			}
			return true
		})

  }

  public void test_contains_nonnull_yes() {
    Iterator<@Nullable String> set = Arrays.<@Nullable String>asList("a", null, "b").iterator();
    assertTrue(Iterators.contains(set, "b"));
  }

  public void test_contains_nonnull_no() {
    Iterator<String> set = asList("a", "b").iterator();
    assertFalse(Iterators.contains(set, "c"));
  }

  public void test_contains_null_yes() {