{!../../docs_src/query_params_str_validations/tutorial002.py!}
```

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
```

      - "9000:9000"
      - "9001:9001"
    depends_on:
      - minio1
      - minio2
      - minio3
      - minio4
      - minio5
      - minio6
      - minio7
      - minio8

## By default this config uses default local driver,
## For custom volumes replace with volume driver configuration.
volumes:
  pdata1-1:
  pdata1-2:
  pdata2-1:
  pdata2-2:
  pdata3-1:
  pdata3-2:
  pdata4-1:
  pdata4-2:

   * constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing
   * user input or falling back to a default enum constant. For example, {@code
   * Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);}
   *
   * @since 12.0
   */
  public static <T extends Enum<T>> Optional<T> getIfPresent(Class<T> enumClass, String value) {
    checkNotNull(enumClass);

  // Depending on whether this is a V2 ckpt, initializes "reader_" or
  // "v2_reader_".
  std::vector<string> v2_path;
  if (Env::Default()->GetMatchingPaths(MetaFilename(filename), &v2_path).ok() &&
      !v2_path.empty()) {
    v2_reader_.reset(
        new BundleReader(Env::Default(), filename /* prefix to a V2 ckpt */));
    if (!v2_reader_->status().ok()) {
      tsl::Set_TF_Status_from_Status(status, v2_reader_->status());

				err = msgp.WrapError(err, "Time")
				return
			}
		case "Token":
			z.Token, err = dc.ReadString()
			if err != nil {
				err = msgp.WrapError(err, "Token")
				return
			}
		default:
			err = dc.Skip()
			if err != nil {
				err = msgp.WrapError(err)
				return
			}
		}
	}
	return
}

// EncodeMsg implements msgp.Encodable

                    "type": "object",
                    "properties": {
                        "description": {"title": "Description", "type": "string"},
                        "type": {"title": "Type", "type": "string", "default": "plane"},
                        "size": {"title": "Size", "type": "integer"},
                    },
                },
                "CarItem": {
                    "title": "CarItem",

from typing_extensions import Annotated


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):
    id: int


class HeroCreate(HeroBase):
    secret_name: str

</html>
"""


@app.get("/")
async def get():
    return HTMLResponse(html)


async def get_cookie_or_token(
    websocket: WebSocket,
    session: Union[str, None] = Cookie(default=None),
    token: Union[str, None] = Query(default=None),
):
    if session is None and token is None:
        raise WebSocketException(code=status.WS_1008_POLICY_VIOLATION)
    return session or token

	if err := d.DecodeElement(&parsedArgs, &start); err != nil {
		return err
	}

	parsedArgs.ContentType = strings.ToLower(parsedArgs.ContentType)
	switch parsedArgs.ContentType {
	case document, lines:
	default:
		return errInvalidJSONType(fmt.Errorf("invalid ContentType '%v'", parsedArgs.ContentType))
	}

	*args = ReaderArgs(parsedArgs)
	args.unmarshaled = true
	return nil
}

# by a third-party and are governed by separate terms of service, privacy
# policy, and support documentation.

name: Scorecard supply-chain security
on:
  # For Branch-Protection check. Only the default branch is supported. See
  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#branch-protection
  branch_protection_rule:
  # To guarantee Maintained check is occasionally updated. See