from fastapi import FastAPI
from fastapi.openapi.docs import (
    get_redoc_html,
    get_swagger_ui_html,
    get_swagger_ui_oauth2_redirect_html,
)
from fastapi.staticfiles import StaticFiles

app = FastAPI(docs_url=None, redoc_url=None)

app.mount("/static", StaticFiles(directory="static"), name="static")


@app.get("/docs", include_in_schema=False)
async def custom_swagger_ui_html():
    return get_swagger_ui_html(

from sqlmodel import Field, Session, SQLModel, create_engine

engine = create_engine("postgresql+psycopg://postgres:postgres@localhost/db")


class User(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str


app = FastAPI()


def get_session():
    with Session(engine) as session:
        yield session

        "lib/gcc/arm-rpi-linux-gnueabihf/**",
        "include/**",
    ]),
)

filegroup(
    name = "aarch64_compiler_pieces",
    srcs = glob([
        "aarch64-none-linux-gnu/**",
        "libexec/**",
        "lib/gcc/aarch64-none-linux-gnu/**",
        "include/**",
    ]),
)

filegroup(
    name = "compiler_components",
    srcs = [
        ":ar",
        ":as",
        ":gcc",

 *
 */
@Deprecated
public final class ArtifactStatus implements Comparable<ArtifactStatus> {
    /**
     * No trust - no information about status.
     */
    public static final ArtifactStatus NONE = new ArtifactStatus("none", 0);

    /**
     * No trust - information was generated with defaults.
     */
    public static final ArtifactStatus GENERATED = new ArtifactStatus("generated", 1);

    /**

```

This means that `item` could be an `int` or a `str`.

#### Possibly `None` { #possibly-none }

You can declare that a value could have a type, like `str`, but that it could also be `None`.

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////

在这种情况下，你可以通过设置 `response_model=None` 来禁用响应模型生成：

{* ../../docs_src/response_model/tutorial003_05_py310.py hl[7] *}

这会让 FastAPI 跳过响应模型的生成，这样你就可以按需使用任意返回类型注解，而不会影响你的 FastAPI 应用。🤓

## 响应模型的编码参数 { #response-model-encoding-parameters }

你的响应模型可以具有默认值，例如：

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None`（或在 Python 3.10 中的 `str | None = None`）默认值为 `None`。

from dataclasses import field  # (1)

from fastapi import FastAPI
from pydantic.dataclasses import dataclass  # (2)


@dataclass
class Item:
    name: str
    description: str | None = None


@dataclass
class Author:
    name: str
    items: list[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)

  @J2ktIncompatible
  @GwtIncompatible // Non-UTF-8 Charset
  public void testUtf16be() {
    assertThat(Charsets.UTF_16BE).isEqualTo(Charset.forName("UTF-16BE"));
  }

  @J2ktIncompatible
  @GwtIncompatible // Non-UTF-8 Charset
  public void testUtf16le() {
    assertThat(Charsets.UTF_16LE).isEqualTo(Charset.forName("UTF-16LE"));
  }

  @J2ktIncompatible
  @GwtIncompatible // Non-UTF-8 Charset
  public void testUtf16() {

     * Consequently:
     * 1. If the previous mean is finite and the new value is non-finite then the new mean is that
     *    value (whether it is NaN or infinity).
     * 2. If the new value is finite and the previous mean is non-finite then the mean is unchanged
     *    (whether it is NaN or infinity).
     * 3. If both the previous mean and the new value are non-finite and...

</div>

Це означає, що воно **завжди матиме значення** - просто іноді це значення може бути `None` (або `null` у JSON).

Отже, клієнтам, які використовують ваш API, не потрібно перевіряти, чи існує значення - вони можуть **припустити, що поле завжди буде присутнє**, але в окремих випадках воно матиме значення за замовчуванням `None`.

У OpenAPI це описується тим, що поле позначається як **обов'язкове**, адже воно завжди присутнє.