```Python
{!> ../../docs_src/security/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/security/tutorial001_an.py!}
```

////

//// tab | Python 3.8+ non-Annotated

/// tip

尽可能选择使用 `Annotated` 的版本。

///

```Python
{!> ../../docs_src/security/tutorial001.py!}
```

////

## 运行

/// info | "说明"

    try {
      equalsTester.testEquals();
    } catch (AssertionFailedError e) {
      assertErrorMessage(e, obj + " must be Object#equals to itself");
      return;
    }
    fail("Should get non-reflexive error");
  }

  /** Test proper handling where an object tests equal to null */
  public void testInvalidEqualsNull() {
    Object obj = new InvalidEqualsNullObject();
    equalsTester.addEqualityGroup(obj);

 * map.put(new Object(), Boolean.TRUE);
 * GcFinalization.awaitDone(new FinalizationPredicate() {
 *   public boolean isDone() {
 *     return map.isEmpty();
 *   }
 * });
 * }</pre>
 *
 * <p>Even if your non-test code does not use finalization, you can use this class to test for
 * leaks, by ensuring that objects are no longer strongly referenced:
 *
 * <pre>{@code
 * // Helper function keeps victim stack-unreachable.

  protected abstract void process(ByteBuffer bb);

  /**
   * This is invoked for the last bytes of the input, which are not enough to fill a whole chunk.
   * The passed {@code ByteBuffer} is guaranteed to be non-empty.
   *
   * <p>This implementation simply pads with zeros and delegates to {@link #process(ByteBuffer)}.
   */
  protected void processRemaining(ByteBuffer bb) {

  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testEntrySet_iteratorRemovePropagates() {
    Iterator<Multiset.Entry<E>> iterator = getMultiset().entrySet().iterator();
    assertTrue(
        "non-empty multiset.entrySet() iterator.hasNext() returned false", iterator.hasNext());
    assertEquals(
        "multiset.entrySet() iterator.next() returned incorrect entry",
        Multisets.immutableEntry(e0(), 1),

   * avoid memory leaks when an element is no longer necessary.
   *
   * <p>This method accepts an array with element type {@code @Nullable T}, but callers must pass an
   * array whose contents are initially non-null. The {@code @Nullable} annotation indicates that
   * this method will write nulls into the array during iteration.
   *
   * <p>This is mainly just to avoid the intermediate ArrayDeque in ConsumingQueueIterator.
   */

    for (int p : NONZERO_INTEGER_CANDIDATES) {
      for (int q : NONZERO_INTEGER_CANDIDATES) {
        for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {
          // Skip some tests that fail due to GWT's non-compliant int implementation.
          // TODO(cpovirk): does this test fail for only some rounding modes or for all?
          if (p == -2147483648 && q == -1 && intsCanGoOutOfRange()) {
            continue;
          }

   *   Iterator<E> i = queue.iterator(); // Must be in synchronized block
   *   while (i.hasNext()) {
   *     foo(i.next());
   *   }
   * }
   * }</pre>
   *
   * <p>Failure to follow this advice may result in non-deterministic behavior.
   *
   * <p>The returned queue will be serializable if the specified queue is serializable.
   *
   * @param queue the queue to be wrapped in a synchronized view

 *
 * <pre>
 * public class PackageSanityTests extends AbstractPackageSanityTests {}
 * </pre>
 *
 * <p>Note that only top-level classes with either a non-private constructor or a non-private static
 * factory method to construct instances can have their instance methods checked. For example:
 *
 * <pre>
 * public class Address {
 *   private final String city;

   * chain:
   *
   * <pre>
   * Iterables.filter(Throwables.getCausalChain(e), IOException.class));
   * </pre>
   *
   * @param throwable the non-null {@code Throwable} to extract causes from
   * @return an unmodifiable list containing the cause chain starting with {@code throwable}
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */