*
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a

 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a

 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a

 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a

 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a

En el mismo punto intentas iniciar el auto-completado con `Ctrl+Space` y ves:

<img src="https://fastapi.tiangolo.com/img/python-types/image02.png">

Con esto puedes moverte hacia abajo viendo las opciones hasta que encuentras una que te suene:

<img src="https://fastapi.tiangolo.com/img/python-types/image03.png">

## Más motivación

Mira esta función que ya tiene type hints:

## Validación de datos

Pero si abres tu navegador en <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a> verás este lindo error de HTTP:

```JSON
{
    "detail": [
        {
            "loc": [
                "path",
                "item_id"
            ],
            "msg": "value is not a valid integer",

 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a

 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a

 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this
 *       to "undo" {@link ElementTypesAreNonnullByDefault}. It is the best we can do for Kotlin
 *       under our current constraints.
 *   <li>NullAway, which will <a