app = FastAPI()

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


class User(BaseModel):
    username: str
    email: Union[str, None] = None
    full_name: Union[str, None] = None
    disabled: Union[bool, None] = None


def fake_decode_token(token):
    return User(
        username=token + "fakedecoded", email="******@****.***", full_name="John Doe"
    )

```

Note que substituímos o valor padrão de `None` para `Query(default=None)`, o primeiro parâmetro de `Query` serve para o mesmo propósito: definir o valor padrão do parâmetro.

Então:

```Python
q: Union[str, None] = Query(default=None)
```

...Torna o parâmetro opcional, da mesma maneira que:

```Python
q: Union[str, None] = None
```

Mas o declara explicitamente como um parâmetro de consulta.

    minimum: Optional[float] = None
    exclusiveMinimum: Optional[float] = None
    maxLength: Optional[int] = Field(default=None, ge=0)
    minLength: Optional[int] = Field(default=None, ge=0)
    pattern: Optional[str] = None
    maxItems: Optional[int] = Field(default=None, ge=0)
    minItems: Optional[int] = Field(default=None, ge=0)
    uniqueItems: Optional[bool] = None
    maxContains: Optional[int] = Field(default=None, ge=0)

											<la:link
												href="/search?q=${f:u(item)}${fe:facetQuery()}${fe:geoQuery()}">${f:h(item)}</la:link>
										</c:if>
										<c:if test="${3 <= s.index}">
											<la:link styleClass="d-none d-sm-inline"
												href="/search?q=${f:u(item)}${fe:facetQuery()}${fe:geoQuery()}">${f:h(item)}</la:link>
										</c:if>
									</c:forEach>
								</p>
							</div>
						</c:if>

        while (true) {
          val socket = serverSocket!!.accept()
          connectionCount.incrementAndGet()
          service(socket)
        }
      } catch (e: SocketException) {
        logger.info("$threadName done accepting connections: ${e.message}")
      } catch (e: IOException) {
        logger.log(Level.WARNING, "$threadName failed unexpectedly", e)
      } finally {
        for (socket in openSockets) {

	// 2: Also block, but with streaming.
	h2 := StreamHandler{
		Handle: func(ctx context.Context, payload []byte, request <-chan []byte, resp chan<- []byte) *RemoteErr {
			gotCall <- struct{}{}
			select {
			case <-ctx.Done():
				gotCall <- struct{}{}
			case <-cleanReqs:
				panic("should not be called")
			}
			return nil
		},
		OutCapacity: 1,
		InCapacity:  1,
	}

	combined.Merge(Mask(mask.Mask()))
	atomic.StoreUint64(&ps.types, uint64(combined))
	if wg != nil {
		wg.Add(1)
	}
	go func() {
		defer func() {
			if wg != nil {
				wg.Done()
			}
			// Clean up and de-register the subscriber
			ps.Lock()
			defer ps.Unlock()
			var remainTypes Mask
			for i, s := range ps.subs {
				if s == sub {

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):

  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Long> none = Arrays.<Long>asList();
    assertThat(Longs.toArray(none)).isEqualTo(EMPTY);

    List<Long> one = Arrays.asList((long) 1);
    assertThat(Longs.toArray(one)).isEqualTo(ARRAY1);

    long[] array = {(long) 0, (long) 1, 0x0FF1C1AL};

re(e,t){for(var n,r,i,o,a,s,u,l=[],c=0,f=e.length;c<f;c++)(r=e[c]).style&&(n=r.style.display,t?("none"===n&&(l[c]=_.get(r,"display")||null,l[c]||(r.style.display="")),""===r.style.display&&ee(r)&&(l[c]=(u=a=o=void 0,a=(i=r).ownerDocument,s=i.nodeName,(u=ne[s])||(o=a.body.appendChild(a.createElement(s)),u=ce.css(o,"display"),o.parentNode.removeChild(o),"none"===u&&(u="block"),ne[s]=u)))):"none"!==n&&(l[c]="none",_.set(r,"display",n)));for(c=0;c<f;c++)null!=l[c]&&(e[c].style.display=l[c]);return e}ce.f...