Pattern.compile("[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}", Pattern.CASE_INSENSITIVE);

    /**
     * Cache for storing resource file modification timestamps to enable cache busting.
     * The cache expires after 10 minutes and has a maximum size of 1000 entries.
     */
    private static LoadingCache<String, Long> resourceHashCache =

    try {
      return super.toString();
    } finally {
      monitor.leave();
    }
  }

  /**
   * Atomically removes all of the elements from this queue. The queue will be empty after this call
   * returns.
   */
  @Override
  public void clear() {
    E[] items = this.items;
    Monitor monitor = this.monitor;
    monitor.enter();
    try {
      int i = takeIndex;

We are importing the submodule `items` directly, instead of importing just its variable `router`.

This is because we also have another variable named `router` in the submodule `users`.

If we had imported one after the other, like:

```Python
from .routers.items import router
from .routers.users import router
```

 *
 * @param <K> the base key type
 * @param <V> the base value type
 * @author Charles Fry
 * @author Jon Donovan
 */
@NullUnmarked
@SuppressWarnings("nullness") // TODO: b/384945891 - Remove after fixing checker.
public class LocalCache<K, V> implements ConcurrentMap<K, V> {
  private static final int UNSET_INT = CacheBuilder.UNSET_INT;

  private final LinkedHashMap<K, Timestamped<V>> cachingHashMap;

   * source Iterable, unless that Iterator is unmodifiable.
   */
  protected abstract I newTargetIterator();

  /**
   * Override this to verify anything after running a list of Stimuli.
   *
   * <p>For example, verify that calls to remove() actually removed the correct elements.
   *
   * @param elements the expected elements passed to the constructor, as mutated by {@code

   * @throws ArithmeticException if {@code mode} is {@link RoundingMode#UNNECESSARY} and {@code x}
   *     is not a power of two
   */
  @SuppressWarnings("fallthrough")
  // TODO(kevinb): remove after this warning is disabled globally
  public static int log2(BigInteger x, RoundingMode mode) {
    checkPositive("x", checkNotNull(x));
    int logFloor = x.bitLength() - 1;
    switch (mode) {
      case UNNECESSARY:

		return errors.New("log buffer full")
	}

	return nil
}

// Cancel - cancels the target.
// All queued messages are flushed and the function returns afterwards.
// All messages sent to the target after this function has been called will be dropped.
func (h *Target) Cancel() {
	h.status.Store(statusClosed)
	h.storeCtxCancel()

	// Wait for messages to be sent...
	h.wg.Wait()

func (r Retention) Retain(created time.Time) bool {
	t, err := UTCNowNTP()
	if err != nil {
		lockLogIf(context.Background(), err)
		// Retain
		return true
	}
	return created.Add(r.Validity).After(t)
}

// DefaultRetention - default retention configuration.
type DefaultRetention struct {
	XMLName xml.Name `xml:"DefaultRetention"`
	Mode    RetMode  `xml:"Mode"`
	Days    *uint64  `xml:"Days"`

func f() {
	print(a)
}

func hello() {
	a = "hello, world"
	go f()
}
</pre>

<p>
calling <code>hello</code> will print <code>"hello, world"</code>
at some point in the future (perhaps after <code>hello</code> has returned).
</p>

<h3 id="goexit">Goroutine destruction</h3>

<p>
The exit of a goroutine is not guaranteed to be synchronized before
any event in the program.

   *
   * <p>This method always throws an exception. The {@code RuntimeException} return type allows
   * client code to signal to the compiler that statements after the call are unreachable. Example
   * usage:
   *
   * <pre>
   * T doSomething() {
   *   try {
   *     return someMethodThatCouldThrowAnything();
   *   } catch (IKnowWhatToDoWithThisException e) {