O parâmetro de consulta `q` é do tipo `str | None`, isso significa que é do tipo `str`, mas também pode ser `None`, e de fato, o valor padrão é `None`, então o FastAPI saberá que não é obrigatório.

/// note | Nota

O FastAPI saberá que o valor de `q` não é obrigatório por causa do valor padrão `= None`.

Ter `str | None` permitirá que seu editor lhe ofereça melhor suporte e detecte erros.

///

from pydantic import BaseModel, SecretStr
from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    github_repository: str
    github_token: SecretStr


class Repo(BaseModel):
    name: str
    html_url: str
    stars: int
    owner_login: str
    owner_html_url: str


def main() -> None:
    logging.basicConfig(level=logging.INFO)
    settings = Settings()

        String str1 = request.getResumeFrom();
        if (properties.containsKey(REMAINING_PROJECTS) && !(str1 != null && !str1.isEmpty())) {
            String propertyValue = properties.getProperty(REMAINING_PROJECTS);
            Stream.of(propertyValue.split(PROPERTY_DELIMITER))
                    .filter(str -> !str.isEmpty())

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009_py39.py!}
```

Wenn Sie `Optional[str]` anstelle von nur `str` verwenden, wird Ihr Editor Ihnen dabei helfen, Fehler zu erkennen, bei denen Sie annehmen könnten, dass ein Wert immer eine String (`str`) ist, obwohl er auch `None` sein könnte.

`Optional[Something]` ist tatsächlich eine Abkürzung für `Union[Something, None]`, diese beiden sind äquivalent.

        // Test default constructor
        String str1 = fileInfo.toString();
        assertNotNull(str1);
        assertTrue(str1.startsWith("EndOfFileInformation["));
        assertTrue(str1.contains("endOfFile="));
        assertTrue(str1.endsWith("]"));

        // Test with specific value
        FileEndOfFileInformation info = new FileEndOfFileInformation(12345L);
        String str2 = info.toString();

class MethodsDependency:
    def synchronous(self, value: str) -> str:
        return value

    async def asynchronous(self, value: str) -> str:
        return value

    def synchronous_gen(self, value: str) -> Generator[str, None, None]:
        yield value

    async def asynchronous_gen(self, value: str) -> AsyncGenerator[str, None]:
        yield value


callable_dependency = CallableDependency()

@pytest.mark.parametrize(
    "path",
    ["/optional-list-str", "/model-optional-list-str"],
)
def test_optional_list_str_missing(path: str):
    client = TestClient(app)
    response = client.post(path)
    assert response.status_code == 200, response.text
    assert response.json() == {"p": None}


@pytest.mark.parametrize(
    "path",
    ["/optional-list-str", "/model-optional-list-str"],
)
def test_optional_list_str(path: str):

}


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    username: str | None = None
    scopes: list[str] = []


class User(BaseModel):
    username: str
    email: str | None = None
    full_name: str | None = None
    disabled: bool | None = None


class UserInDB(User):
    hashed_password: str


password_hash = PasswordHash.recommended()

      assertFalse(str, c == Ascii.toUpperCase(c));
      assertTrue(str, Ascii.isLowerCase(c));
      assertFalse(str, Ascii.isUpperCase(c));
    }
  }

  public void testCharsUpper() {
    for (char c : UPPER.toCharArray()) {
      String str = String.valueOf(c);
      assertFalse(str, c == Ascii.toLowerCase(c));
      assertTrue(str, c == Ascii.toUpperCase(c));
      assertFalse(str, Ascii.isLowerCase(c));

        String str = info.toString();

        // Verify string contains expected elements
        assertNotNull(str);
        assertTrue(str.startsWith("SmbShareInfo["));
        assertTrue(str.contains("netName=" + TEST_NET_NAME));
        assertTrue(str.contains("type=0x"));
        assertTrue(str.contains("remark=" + TEST_REMARK));
        assertTrue(str.endsWith("]"));
    }

    @Test