*/
public abstract class ConstructorUtil {

    /**
     * Do not instantiate.
     */
    protected ConstructorUtil() {
    }

    /**
     * Creates and initializes a new instance of the class declared by the specified constructor with the given initialization parameters.
     *
     * @param <T> the type of the object
     * @param constructor the constructor (must not be {@literal null})

	constChase  = AIsLowerA  // forward declaration to exported ident

	// Deprecated: use B.
	A         = 1
	a         = 11
	A64 int64 = 1

	AIsLowerA = a // previously declared
)

const (
	ConversionConst = MyInt(5)
)

// Variables from function calls.
var (
	V = ptwo.F()
	// Deprecated: use WError.
	VError = BarE()
	V1     = Bar1(1, 2, 3)
	V2     = ptwo.G()
)

Par défaut, FastAPI renvoie des réponses JSON.

Si vous déclarez un [Modèle de réponse](../tutorial/response-model.md), FastAPI l'utilisera pour sérialiser les données en JSON, en utilisant Pydantic.

Si vous ne déclarez pas de modèle de réponse, FastAPI utilisera le `jsonable_encoder` expliqué dans [Encodeur compatible JSON](../tutorial/encoder.md) et le placera dans une `JSONResponse`.

* The user types the `username` and `password` in the frontend, and hits `Enter`.
* The frontend (running in the user's browser) sends that `username` and `password` to a specific URL in our API (declared with `tokenUrl="token"`).
* The API checks that `username` and `password`, and responds with a "token" (we haven't implemented any of this yet).

- L'utilisateur saisit le `username` et le `password` dans le frontend, puis appuie sur Entrée.
- Le frontend (exécuté dans le navigateur de l'utilisateur) envoie ce `username` et ce `password` vers une URL spécifique de notre API (déclarée avec `tokenUrl="token"`).
- L'API vérifie ce `username` et ce `password`, et répond avec un « token » (nous n'avons encore rien implémenté de tout cela).

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

Because each SQLModel model is also a Pydantic model, you can use it in the same **type annotations** that you could use Pydantic models.

For example, if you declare a parameter of type `Hero`, it will be read from the **JSON body**.

The same way, you can declare it as the function's **return type**, and then the shape of the data will show up in the automatic API docs UI.