* @return RDMA provider instance, or null if none available
     */
    public static RdmaProvider getProvider(Configuration config) {
        String preference = config.getRdmaProvider();
        return createProvider(preference != null ? preference : "auto");
    }

    /**
     * Select the best available RDMA provider
     *
     * @return best RDMA provider, or null if none available
     */

/// tip | Dica

Fazer com que o modelo de retorno garanta que um valor esteja sempre disponível e sempre seja um `int` (não `None`) é muito útil para os clientes da API, eles podem escrever código muito mais simples com essa certeza.

c,d,e,f=[],g=0,h=a.length;h>g;g++)d=a[g],d.style&&(f[g]=L.get(d,"olddisplay"),c=d.style.display,b?(f[g]||"none"!==c||(d.style.display=""),""===d.style.display&&S(d)&&(f[g]=L.access(d,"olddisplay",tb(d.nodeName)))):(e=S(d),"none"===c&&e||L.set(d,"olddisplay",e?c:n.css(d,"display"))));for(g=0;h>g;g++)d=a[g],d.style&&(b&&"none"!==d.style.display&&""!==d.style.display||(d.style.display=b?f[g]||"":"none"));return a}n.extend({cssHooks:{opacity:{get:function(a,b){if(b){var c=xb(a,"opacity");return""===c?"1...

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

The modules under this directory will be released exactly once each. Once that

    your response for more than 2 weeks.

**4. Approved**

-   Once the PR is approved, it gets `kokoro:force-run` label applied and it
    initiates CI/CD tests.
-   We can't move forward if these tests fail.
-   In such situations, we may request you to make further changes to your PR
    for the tests to pass.
-   Once the tests pass, we now bring all the code into the internal code base,

</div>

Esto significa que **siempre tendrá un valor**, solo que a veces el valor podría ser `None` (o `null` en JSON).

Eso significa que, los clientes que usan tu API no tienen que comprobar si el valor existe o no, pueden **asumir que el campo siempre estará allí**, pero solo que en algunos casos tendrá el valor por defecto de `None`.

La forma de describir esto en OpenAPI es marcar ese campo como **requerido**, porque siempre estará allí.

</div>

Das bedeutet, dass es **immer einen Wert** hat, der Wert kann jedoch manchmal `None` sein (oder `null` in JSON).

Das bedeutet, dass Clients, die Ihre API verwenden, nicht prüfen müssen, ob der Wert vorhanden ist oder nicht. Sie können davon ausgehen, dass das Feld immer vorhanden ist. In einigen Fällen hat es jedoch nur den Defaultwert `None`.

        """
        if self.cid is not None:
            fetcher = self._create_credentials_fetcher()
            return RefreshableCredentials.create_from_metadata(
                metadata=fetcher(),
                refresh_using=fetcher,
                method=self.METHOD,
            )
        else:
            return None

    def _create_credentials_fetcher(self):
        method = self.METHOD