say_hi(name=None)  # Dit werkt, None is geldig 🎉
```

Het goede nieuws is dat als je eenmaal Python 3.10 gebruikt, je je daar geen zorgen meer over hoeft te maken, omdat je dan gewoon `|` kunt gebruiken om unions van types te definiëren:

{* ../../docs_src/python_types/tutorial009c_py310.py hl[1,4] *}


Dan hoef je je geen zorgen te maken over namen als `Optional` en `Union`. 😎

#### Generieke typen

## Installatie

<div class="termy">

```console
$ pip install "fastapi[standard]"

---> 100%
```

</div>

**Opmerking**: Zet `"fastapi[standard]"` tussen aanhalingstekens om ervoor te zorgen dat het werkt in alle terminals.

## Voorbeeld

### Creëer het

* Maak het bestand `main.py` aan met daarin:

```Python
from typing import Union

from fastapi import FastAPI

{* ../../docs_src/security/tutorial001_an_py39.py hl[8] *}

/// tip

Here `tokenUrl="token"` refers to a relative URL `token` that we haven't created yet. As it's a relative URL, it's equivalent to `./token`.

Actualiza `get_current_user` para recibir el mismo token que antes, pero esta vez, usando tokens JWT.

Decodifica el token recibido, verifícalo y devuelve el usuario actual.

Si el token es inválido, devuelve un error HTTP de inmediato.

{* ../../docs_src/security/tutorial004_an_py310.py hl[90:107] *}

## Actualizar la *path operation* `/token`

Crea un `timedelta` con el tiempo de expiración del token.

    public String token;

    /**
     * The permissions associated with this access token.
     * Defines what operations and resources this token can access.
     */
    @CustomSize(maxKey = "form.admin.max.input.size")
    public String permissions;

    /**
     * The parameter name for the access token.
     * This field specifies how the token should be passed in API requests.
     * Maximum length is 10000 characters.

        }, "A PACDecodingException should be thrown for a malformed token.");

        assertEquals("Malformed kerberos ticket", exception.getMessage(), "The exception message should indicate a malformed ticket.");
    }

    /**
     * Test constructor with an empty token.
     * Empty token causes readObject() to return null, which leads to NullPointerException.
     */
    @Test

     *
     * @param id The ID of the item.
     * @param token The token.
     * @param segmentation The segmentation.
     * @param reading The reading.
     * @param pos The part of speech.
     */
    public KuromojiItem(final long id, final String token, final String segmentation, final String reading, final String pos) {
        this.id = id;
        this.token = token;
        this.segmentation = segmentation;

    }

    /**
     * Constructs a NegTokenInit by parsing the provided token bytes
     * @param token the SPNEGO token bytes to parse
     * @throws IOException if parsing fails
     */
    public NegTokenInit(final byte[] token) throws IOException {
        parse(token);
    }

    /**
     * Gets the context flags indicating security capabilities

 * <li>TOKEN_NAME - The name of the token parameter.</li>
 * <li>TOKEN_METHOD - The HTTP method to use for the token request (GET or POST).</li>
 * <li>TOKEN_PARAMTERS - The parameters to include in the token request.</li>
 * <li>LOGIN_METHOD - The HTTP method to use for the login request (GET or POST).</li>
 * <li>LOGIN_URL - The URL to send the login request to.</li>

    void testParseRejectsUnknownField() throws Exception {
        ASN1TaggedObject unknown = new DERTaggedObject(true, 7, new DEROctetString(new byte[] { 0x01 }));
        byte[] token = buildInitToken(new ASN1ObjectIdentifier[] { OID_KRB }, 0, null, null, false, null, null, unknown);

        IOException ex = assertThrows(IOException.class, () -> new NegTokenInit(token));