popular format
   * The main mime type should be the canonical one, use aliases for any
     other widely used forms
   * Where there's a hierarchy in the types, list it via a parent
   * Highly specific magic matches get a high priority
   * General magic matches which could trigger a false-positive need
     a low one
   * The priority for containers normally need to be higher than for

            "description": "A very nice Item",
            "price": 35.4,
            "tax": 3.2,
        },
    )
    assert response.status_code == 200


def test_openapi_schema(client: TestClient) -> None:
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},

            "price": 35.4,
            "tax": 3.2,
        },
    )
    assert response.status_code == 200


@needs_py310
def test_openapi_schema(client: TestClient) -> None:
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},

import java.io.PrintWriter;
import java.util.Collection;
import java.util.Map;

@NonNullApi
@CacheableTask
public abstract class GenerateApiMapping extends DefaultTask {
    @PathSensitive(PathSensitivity.NONE)
    @InputFile
    public abstract RegularFileProperty getMetaDataFile();

    @OutputFile
    public abstract RegularFileProperty getMappingDestFile();

    /**

 * @author shot
 * @author manhole
 */
public class EnumerationIteratorTest {

    /**
     * @see org.junit.rules.ExpectedException
     */
    @Rule
    public ExpectedException exception = ExpectedException.none();

    /**
     *
     */
    @Test
    public void testEnumerationIterator() {
        final Vector<String> vector = new Vector<String>();
        vector.add("a");

     */
    Map<String, String> getUserProperties();

    /**
     * Gets the base directory of the current project (if any).
     *
     * @return The base directory of the current project or {@code null} if none.
     */
    File getProjectDirectory();

    /**
     * Gets current calculated project properties
     *
     * @return The project properties, never {@code null}.
     */

```Python
print(user_dict)
```

мы можем получить `dict` с такими данными:

```Python
{
    'username': 'john',
    'password': 'secret',
    'email': 'john.doe@example.com',
    'full_name': None,
}
```

#### Распаковка `dict`

```Python
print(user_dict)
```

teríamos um `dict` Python com:

```Python
{
    'username': 'john',
    'password': 'secret',
    'email': 'john.doe@example.com',
    'full_name': None,
}
```

#### Desembrulhando um `dict`

```
INFO: Sending request http://www.publicobject.com/helloworld.txt on Connection{www.publicobject.com:80, proxy=DIRECT hostAddress=54.187.32.157 cipherSuite=none protocol=http/1.1}
User-Agent: OkHttp Example
Host: www.publicobject.com
Connection: Keep-Alive
Accept-Encoding: gzip

INFO: Received response for http://www.publicobject.com/helloworld.txt in 115.6ms

```

クエリパラメータの宣言と同様に、モデル属性がデフォルト値をもつとき、必須な属性ではなくなります。それ以外は必須になります。オプショナルな属性にしたい場合は `None` を使用してください。

例えば、上記のモデルは以下の様なJSON「`オブジェクト`」(もしくはPythonの `dict` ) を宣言しています:

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

...`description` と `tax` はオプショナル (デフォルト値は `None`) なので、以下のJSON「`オブジェクト`」も有効です:

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