Another big feature needed by APIs is data validation, making sure that the data is valid, given certain parameters. For example, that some field is an `int`, and not some random string. This is especially useful for incoming data.

Without a data validation system, you would have to do all the checks by hand, in code.

      WrappedIterator(Iterator<V> delegateIterator) {
        this.delegateIterator = delegateIterator;
      }

      /**
       * If the delegate changed since the iterator was created, the iterator is no longer valid.
       */
      void validateIterator() {
        refreshIfEmpty();
        if (delegate != originalDelegate) {
          throw new ConcurrentModificationException();
        }
      }

    containing an IP address we must match that address against the URL's IP address, even when the
    two addresses are encoded differently, such as `192.168.1.1` and `0::0:0:FFFF:C0A8:101`. Note
    that OkHttp incorrectly rejected valid certificates resulting in a failure to connect; at no
    point were invalid certificates accepted.
 *  New: `OkHttpClient.Builder.minWebSocketMessageToCompress()` configures a threshold for

)

const (
	maxEConfigJSONSize        = 262272
	kubernetesVersionEndpoint = "https://kubernetes.default.svc/version"
	anonymizeParam            = "anonymize"
	anonymizeStrict           = "strict"
)

// Only valid query params for mgmt admin APIs.
const (
	mgmtBucket      = "bucket"
	mgmtPrefix      = "prefix"
	mgmtClientToken = "clientToken"
	mgmtForceStart  = "forceStart"
	mgmtForceStop   = "forceStop"
)

Depois ele irá converter e validar os dados. Assim, quando você utilizar aquele objeto `settings`, os dados terão o tipo que você declarou (e.g. `items_per_user` será do tipo `int`).

### Usando o objeto `settings`

      assertTrue(
          LongMath.biggestBinomials[k] == Integer.MAX_VALUE
              || !fitsInLong(BigIntegerMath.binomial(LongMath.biggestBinomials[k] + 1, k)));
      // In the first case, any long is valid; in the second, we want to test that the next-bigger
      // long overflows.
    }
    int k = LongMath.biggestBinomials.length;
    assertFalse(fitsInLong(BigIntegerMath.binomial(2 * k, k)));

          escapedInput.append(c);
        } else {
          escapedInput.append(String.format("\\u%04x", (int) c));
        }
      }
      fail("FLOATING_POINT_PATTERN should have matched valid input <" + escapedInput + ">");
    }
  }

  @GwtIncompatible // Doubles.tryParse
  private static void checkTryParse(double expected, String input) {

// It also fills out fields (uname, gname, devmajor, devminor) that are
// shared in the USTAR, PAX, and GNU formats using the provided formatters.
//
// The block returned is only valid until the next call to
// templateV7Plus or writeRawFile.
func (tw *Writer) templateV7Plus(hdr *Header, fmtStr stringFormatter, fmtNum numberFormatter) *block {
	tw.blk.reset()

	modTime := hdr.ModTime

	expiresStr := req.Header.Get("Expires")
	if expiresStr == "" {
		expiresStr = strconv.FormatInt(epochExpires, 10)
		req.Header.Set("Expires", expiresStr)
	}

	// url.RawPath will be valid if path has any encoded characters, if not it will
	// be empty - in which case we need to consider url.Path (bug in net/http?)
	encodedResource := req.URL.RawPath
	encodedQuery := req.URL.RawQuery
	if encodedResource == "" {

    * Parámetros de path.
    * Parámetros de query.
    * Cookies.
    * Headers.
    * Forms.
    * Archivos.
* <abbr title="también conocido como: serialización, parsing, marshalling">Conversión</abbr> de datos de salida: convirtiendo de datos y tipos de Python a datos de red (como JSON):
    * Convertir tipos de Python (`str`, `int`, `float`, `bool`, `list`, etc).
    * Objetos `datetime`.
    * Objetos `UUID`.