```Python hl_lines="2  7-10  23-25"
from fastapi import FastAPI
from pydantic import BaseModel
from typing import Union

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):

```Python hl_lines="4  9-12  25-27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

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):

```Python hl_lines="2  7-10  23-25"
from fastapi import FastAPI
from pydantic import BaseModel
from typing import Optional

app = FastAPI()


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


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


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

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...оскільки `description` і `tax` є необов'язковими (зі значенням за замовчуванням `None`), цей JSON "`об'єкт`" також буде дійсним:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Оголоси її як параметр

### Usage

```
minio server --config config.yaml
```

        '0', '1', '2', '3', '4', '5',
        '6', '7', '8', '9', 'A', 'B',
        'C', 'D', 'E', 'F'
    };

/** 
 * Generate "hexdump" output of the buffer at src like the following:
 *
 * <p><blockquote><pre>
 * 00000: 04 d2 29 00 00 01 00 00 00 00 00 01 20 45 47 46  |..)......... EGF|
 * 00010: 43 45 46 45 45 43 41 43 41 43 41 43 41 43 41 43  |CEFEECACACACACAC|
 * 00020: 41 43 41 43 41 43 41 43 41 43 41 41 44 00 00 20  |ACACACACACAAD.. |

 * annotated by {@link TestSubtype}.
 *
 * <p>These declaration methods rely on Java static type checking to make sure what we want to
 * assert as subtypes are really subtypes according to javac. For example:
 *
 * <pre>{@code
 * class MySubtypeTests extends SubtypeTester {
 *   @TestSubtype(suppressGetSubtype = true, suppressGetSupertype = true)
 *   public <T> Iterable<? extends T> listIsSubtypeOfIterable(List<T> list) {

   * not propagated (otherwise the original exception will be lost).
   *
   * <p>If {@code swallowIOException} is true then we never throw {@code IOException} but merely log
   * it.
   *
   * <p>Example:
   *
   * <pre>{@code
   * public void useStreamNicely() throws IOException {
   *   SomeStream stream = new SomeStream("foo");
   *   boolean threw = true;
   *   try {
   *     // ... code which does something with the stream ...

  }

  /**
   * A builder for creating {@link ImmutableValueGraph} instances, especially {@code static final}
   * graphs. Example:
   *
   * <pre>{@code
   * static final ImmutableValueGraph<City, Distance> CITY_ROAD_DISTANCE_GRAPH =
   *     ValueGraphBuilder.undirected()
   *         .<City, Distance>immutable()

     * {@link #format(String, Object...)}を{@literal static import}しておくと便利です。
     * </p>
     *
     * <pre>
     * import static org.codelibs.core.log.Logger.format;
     *
     * Logger logger = Logger.getLogger(Xxx.class);
     * logger.log(format("DXXX0000", arg1, arg2, arg3));
     * </pre>
     *
     * @param logMessage
     *            ログメッセージ。{@literal null}であってはいけません
     */