ticker.advance(1, MILLISECONDS);
    assertThat(keySet).containsExactly(2, 3, 4, 5, 6, 7, 8, 9, 0);

    // get(K, Callable) doesn't stop 2 from expiring
    Integer unused = cache.get(2, Callables.returning(-2));
    CacheTesting.drainRecencyQueues(cache);
    ticker.advance(1, MILLISECONDS);
    assertThat(keySet).containsExactly(3, 4, 5, 6, 7, 8, 9, 0);

    // asMap.put saves 3
    cache.asMap().put(3, -3);

    ListeningExecutorService service = listeningDecorator(newDirectExecutorService());
    assertSame(service, listeningDecorator(service));
    List<Callable<String>> callables = ImmutableList.of(Callables.returning("x"));
    List<Future<String>> results;

    results = service.invokeAll(callables);
    assertThat(getOnlyElement(results)).isInstanceOf(TrustedListenableFutureTask.class);

			},
			nil, nil,
		},
		// Checks if wrapped context cancellation errors are grouped as one.
		{canceledErrs, nil, context.Canceled},
	}
	// Validates list of all the testcases for returning valid errors.
	for i, testCase := range testCases {
		gotErr := reduceReadQuorumErrs(t.Context(), testCase.errs, testCase.ignoredErrs, 5)
		if gotErr != testCase.err {

    } catch (UnsupportedOperationException e) {
      return;
    }

    Set<Entry<K, V>> entrySet = map.entrySet();
    if (supportsRemove) {
      try {
        entrySet.retainAll(null);
        // Returning successfully is not ideal, but tolerated.
      } catch (NullPointerException tolerated) {
      }
    } else {
      try {
        entrySet.retainAll(null);

# Background Tasks { #background-tasks }

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

			return
		case <-t.C:
			m.lastHandout = time.Now()

			if m2, err := rpc.UpdateMetacacheListing(ctx, m); err == nil {
				if m2.status != scanStateStarted {
					if serverDebugLog {
						console.Debugln("returning", m.id, "due to scan state", m2.status, time.Now().Format(time.RFC3339))
					}
					return
				}
				m = m2
				if serverDebugLog {
					console.Debugln("refreshed", m.id, time.Now().Format(time.RFC3339))

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example { #a-dict-from-the-previous-example }

In the previous example, we were returning a `dict` from our dependency ("dependable"):

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

But then we get a `dict` in the parameter `commons` of the *path operation function*.

	for rng, val := range values {
		m.Set(name, float64(val), append(labels, rangeL, rng)...)
	}
}

// MetricsLoaderFn - represents a function to load metrics from the
// metricsCache.
//
// Note that returning an error here will cause the Metrics handler to return a
// 500 Internal Server Error.
type MetricsLoaderFn func(context.Context, MetricValues, *metricsCache) error

// getScannedItemsMap - returns map of all scanned items against type
func (h *healSequence) getScannedItemsMap() map[madmin.HealItemType]int64 {
	h.mutex.RLock()
	defer h.mutex.RUnlock()

	// Make a copy before returning the value
	retMap := make(map[madmin.HealItemType]int64, len(h.scannedItemsMap))
	maps.Copy(retMap, h.scannedItemsMap)

	return retMap
}

// getHealedItemsMap - returns the map of all healed items against type

    ListeningExecutorService service = listeningDecorator(newDirectExecutorService());
    assertSame(service, listeningDecorator(service));
    List<Callable<String>> callables = ImmutableList.of(Callables.returning("x"));
    List<Future<String>> results;

    results = service.invokeAll(callables);
    assertThat(getOnlyElement(results)).isInstanceOf(TrustedListenableFutureTask.class);