```Python hl_lines="24"
    {!> ../../../docs_src/response_model/tutorial004.py!}
    ```

and those default values won't be included in the response, only the values actually set.

So, if you send a request to that *path operation* for the item with ID `foo`, the response (not including default values) will be:

```JSON
{
    "name": "Foo",
    "price": 50.2
}
```

!!! info

@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"X-Token values": None}),
        ("/items", {"x-token": "foo"}, 200, {"X-Token values": ["foo"]}),
        (
            "/items",
            [("x-token", "foo"), ("x-token", "bar")],
            200,
            {"X-Token values": ["foo", "bar"]},
        ),
    ],
)
def test(path, headers, expected_status, expected_response):

By inheriting from `str` the API docs will be able to know that the values must be of type `string` and will be able to render correctly.

Then create class attributes with fixed values, which will be the available valid values:

```Python hl_lines="1  6-9"
{!../../../docs_src/path_params/tutorial005.py!}
```

!!! info

            """
        ),
    ] = _Unset,
    examples: Annotated[
        Optional[List[Any]],
        Doc(
            """
            Example values for this field.
            """
        ),
    ] = None,
    example: Annotated[
        Optional[Any],
        deprecated(
            "Deprecated in OpenAPI 3.1.0 that now uses JSON Schema 2020-12, "

        if use_type is None:
            use_type = create_model(original_type.__name__, __base__=original_type)
            cloned_types[original_type] = use_type
            for f in original_type.__fields__.values():
                use_type.__fields__[f.name] = create_cloned_field(
                    f, cloned_types=cloned_types
                )
    new_field = create_response_field(name=field.name, type_=use_type)

Here we'll see an example using **<a href="https://www.couchbase.com/" class="external-link" target="_blank">Couchbase</a>**, a <abbr title="Document here refers to a JSON object (a dict), with keys and values, and those values can also be other JSON objects, arrays (lists), numbers, strings, booleans, etc.">document</abbr> based NoSQL database.

You can adapt it to any other NoSQL database like:

* **MongoDB**
* **Cassandra**

```Python hl_lines="1"
{!../../../docs_src/python_types/tutorial005.py!}
```

### Generic types with type parameters

There are some data structures that can contain other values, like `dict`, `list`, `set` and `tuple`. And the internal values can have their own type too.

These types that have internal types are called "**generic**" types. And it's possible to declare them, even with their internal types.

### Step 5: return the content

```Python hl_lines="8"
{!../../../docs_src/first_steps/tutorial001.py!}
```

You can return a `dict`, `list`, singular values as `str`, `int`, etc.

You can also return Pydantic models (you'll see more about that later).

    {!> ../../../docs_src/header_params/tutorial003.py!}
    ```

与*路径操作*通信时，以下面的方式发送两个 HTTP 请求头：

```
X-Token: foo
X-Token: bar
```

响应结果是：

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

## 小结

使用 `Header` 声明请求头的方式与 `Query`、`Path` 、`Cookie` 相同。

## Query parameter list / multiple values

When you define a query parameter explicitly with `Query` you can also declare it to receive a list of values, or said in other way, to receive multiple values.

For example, to declare a query parameter `q` that can appear multiple times in the URL, you can write:

=== "Python 3.10+"