```Python hl_lines="1"
{!../../docs_src/python_types/tutorial003.py!}
```

Como el editor conoce el tipo de las variables no solo obtienes auto-completado, si no que también obtienes chequeo de errores:

<img src="https://fastapi.tiangolo.com/img/python-types/image04.png">

Ahora que sabes que tienes que arreglarlo convierte `age` a un string con `str(age)`:

```Python hl_lines="2"

El mismo error aparecería si pasaras un `float` en vez de un `int` como en: <a href="http://127.0.0.1:8000/items/4.2" class="external-link" target="_blank">http://127.0.0.1:8000/items/4.2</a>

/// check | Revisa

Así, con la misma declaración de tipo de Python, **FastAPI** te da validación de datos.

Observa que el error también muestra claramente el punto exacto en el que no pasó la validación.

func checkFields(un *unstructured.Unstructured) error {
	var errs error
	for key := range un.Object {
		if _, ok := validFields[key]; !ok {
			errs = multierror.Append(errs, fmt.Errorf("unknown field %q", key))
		}
	}
	return errs
}

func (v *validator) validateResource(istioNamespace, defaultNamespace string, un *unstructured.Unstructured, writer io.Writer) (validation.Warning, error) {
	g := config.GroupVersionKind{

 * or both.
 *
 * ## Authentication Retries
 *
 * If your authentication may be flaky and requires retries you should apply some policy
 * to limit the retries by the class of errors and number of attempts.  To get the number of
 * attempts to the current point use this function.
 *
 * ```java
 * private int responseCount(Response response) {
 *   int result = 1;

    private List<CyclicDependencyException> circularDependencyExceptions;

    private List<ArtifactResolutionException> errorArtifactExceptions;

    // file system errors

    private List<ArtifactRepository> repositories;

    private Set<Artifact> requestedArtifacts;

    private Set<Artifact> artifacts;

    private MetadataGraph dirtyTree;

/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.

The `Union` in `Union[str, None]` will allow your editor to give you better support and detect errors.

///

## Additional validation

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

### Import `Query` and `Annotated`

  go func() {
   for {
    // Reconnect if the connection is lost.
    if stanConnection == nil || stanConnection.NatsConn() == nil ||  !stanConnection.NatsConn().IsConnected() {
     stanConnection, _ = stan.Connect("test-cluster", "test-client", stan.NatsURL("nats://yourusername:yoursecret@0.0.0.0:4222"), stan.SetConnectionLostHandler(func(c stan.Conn, _ error) {
      if c.NatsConn() != nil {

			cd, _ := os.ReadFile(fmt.Sprintf("testdata/routes/%s/configdump.json", tt.name))
			if err := cw.Prime(cd); err != nil {
				t.Errorf("failed to parse config dump: %s", err)
			}
			err := cw.PrintRouteSummary(RouteFilter{Verbose: true})
			assert.NoError(t, err)

			wantOutputFile := path.Join("testdata/routes", tt.name, "output.txt")
			util.CompareContent(t, gotOut.Bytes(), wantOutputFile)
		})
	}

		Name:      "errors_timeout",
		Help:      "Total number of drive timeout errors since server uptime",
		Type:      counterMetric,
	}
}

func getNodeDriveIOErrorsMD() MetricDescription {
	return MetricDescription{
		Namespace: nodeMetricNamespace,
		Subsystem: driveSubsystem,
		Name:      "errors_ioerror",
		Help:      "Total number of drive I/O errors since server uptime",
		Type:      counterMetric,
	}
}

			// If there is a disconnection before globalNetPerfMinDuration (we give a margin of error of 1 sec)
			// would mean the network is not stable. Logging here will help in debugging network issues.
			if time.Since(connectTime) < (globalNetPerfMinDuration - time.Second) {
				adminLogIf(ctx, err)
			}
		}
		if err != nil {
			if errors.Is(err, io.EOF) {
				w.WriteHeader(http.StatusNoContent)
			} else {