<p>
A read <i>r</i> of a memory location <i>x</i>
holding a value
that is not larger than a machine word must observe
some write <i>w</i> such that <i>r</i> does not happen before <i>w</i>
and there is no write <i>w'</i> such that <i>w</i> happens before <i>w'</i>
and <i>w'</i> happens before <i>r</i>.
That is, each read must observe a value written by a preceding or concurrent write.
</p>

<p>

		return
	}

	if w != nil {
		// Increment the prometheus http request response histogram with API, Bucket
		bucketHTTPRequestsDuration.With(prometheus.Labels{
			"api":    api,
			"bucket": bucket,
		}).Observe(w.TimeToFirstByte.Seconds())
	}

	bh.Lock()
	defer bh.Unlock()

	hstats, ok := bh.httpStats[bucket]
	if !ok {
		hstats = bucketHTTPAPIStats{
			currentS3Requests: &HTTPAPIStats{},

		// observations. This is to test the channel based
		// synchronization used internally.
		select {
		case <-ticker.C:
			ttfbHist.With(prometheus.Labels{"api": obs.label}).Observe(obs.val)
		}
	}

	metrics := getHistogramMetrics(ttfbHist, getBucketTTFBDistributionMD(), false)
	// additional labels for +Inf for all histogram metrics

		Buckets: []float64{0.01, 0.1, 1, 2, 5, 10, 60, 5 * 60, 15 * 60, 30 * 60},
	}, []string{"tier"}),
}

func (t *tierMetrics) Observe(tier string, dur time.Duration) {
	t.histogram.With(prometheus.Labels{"tier": tier}).Observe(dur.Seconds())
}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++

```JSON
{"item_id":3}
```

!!! check "Verifique"
	Observe que o valor recebido pela função (e também retornado por ela) é `3`, como um Python `int`, não como uma string `"3"`.

   *
   * The problem with these is that remove(K, long) has to be done in two phases by definition ---
   * first decrementing to zero, and then removing. putIfAbsent or replace could observe the
   * intermediate zero-state. Ways we could deal with this are:
   *
   * - Don't define any of the ConcurrentMap operations. This is the current state of affairs.
   *

Ao fazer isso, seu editor pode fornecer suporte mesmo durante o processamento de itens da lista:

<img src="/img/python-types/image05.png">

Sem tipos, isso é quase impossível de alcançar.

Observe que a variável `item` é um dos elementos da lista `items`.

E, ainda assim, o editor sabe que é um `str` e fornece suporte para isso.

#### `Tuple` e `Set`

Você faria o mesmo para declarar `tuple`s e `set`s:

  builder: Builder,
) : Call.Factory, WebSocket.Factory {
  @get:JvmName("dispatcher")
  val dispatcher: Dispatcher = builder.dispatcher

  /**
   * Returns an immutable list of interceptors that observe the full span of each call: from before
   * the connection is established (if any) until after the response source is selected (either the
   * origin server, cache, or both).
   */
  @get:JvmName("interceptors")

  /**
   * The HTTP <a href="https://patcg-individual-drafts.github.io/topics/">{@code
   * Observe-Browsing-Topics}</a> header field name.
   *
   * @since 32.0.0
   */
  public static final String OBSERVE_BROWSING_TOPICS = "Observe-Browsing-Topics";

  /**
   * The HTTP <a
   * href="https://wicg.github.io/turtledove/#handling-direct-from-seller-signals">{@code

                "Overflow adding " + occurrences + " occurrences to a count of " + oldValue);
          }
        } else {
          // In the case of a concurrent remove, we might observe a zero value, which means another
          // thread is about to remove (element, existingCounter) from the map. Rather than wait,
          // we can just do that work here.