/// tip

默认语言是英语，位于 `docs/en/`目录。

///

现在为西班牙语文档运行实时服务器：

<div class="termy">

```console
// Use the command "live" and pass the language code as a CLI argument
$ python ./scripts/docs.py live es

<span style="color: green;">[INFO]</span> Serving on http://127.0.0.1:8008
<span style="color: green;">[INFO]</span> Start watching changes

@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Collections2 {
  private Collections2() {}

  /**
   * Returns the elements of {@code unfiltered} that satisfy a predicate. The returned collection is
   * a live view of {@code unfiltered}; changes to one affect the other.
   *
   * <p>The resulting collection's iterator does not support {@code remove()}, but all other

  // For example: (long) data[i++] | (long) data[i++] << 8 | ...
  // If data[i] == (byte) 0x80, the first cast will sign-extend it to 0xffffffffffffff80,
  // masking the remaining seven bytes.
  // To test this, we give an input where bit 7 is not cleared. For example:
  // (1) 00 01 02 03 04 05 06 07 80
  // (2) 00 01 02 03 04 05 06 07 81
  // (3) 00 01 02 03 04 05 06 07 ff (or anything in between)

  // For example: (long) data[i++] | (long) data[i++] << 8 | ...
  // If data[i] == (byte) 0x80, the first cast will sign-extend it to 0xffffffffffffff80,
  // masking the remaining seven bytes.
  // To test this, we give an input where bit 7 is not cleared. For example:
  // (1) 00 01 02 03 04 05 06 07 80
  // (2) 00 01 02 03 04 05 06 07 81
  // (3) 00 01 02 03 04 05 06 07 ff (or anything in between)

  private ClassToInstanceMap<Number> map;

  @Override
  protected void setUp() throws Exception {
    map = MutableClassToInstanceMap.create();
  }

  public void testConstraint() {

    /**
     * We'll give ourselves a pass on testing all the possible ways of breaking the constraint,
     * because we know that newClassMap() is implemented using ConstrainedMap which is itself

///

```Python hl_lines="7-12  16"
{!> ../../docs_src/header_param_models/tutorial001_py310.py!}
```

////

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs

You can see the required headers in the docs UI at `/docs`:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

   * compatible with HTML. Specifically, it does not perform entity replacement (symbolic or
   * numeric), so it does not replace non-ASCII code points with character references. This escaper
   * escapes only the following five ASCII characters: {@code '"&<>}.
   */
  public static Escaper htmlEscaper() {
    return HTML_ESCAPER;
  }

  // For each xxxEscaper() method, please add links to external reference pages

        But Guava aims to provide functionality that is useful across boundaries of projects,
        companies, or even industries — utilities useful for a sizable proportion of all Java
        programmers everywhere. If you can give enough detail such that any of us can imagine coming
        across a similar need in our own work, that's extremely helpful in studying how broadly
        useful the proposed change will be.

  - type: textarea

///

```Python hl_lines="9-12  16"
{!> ../../docs_src/cookie_param_models/tutorial001.py!}
```

////

**FastAPI** will **extract** the data for **each field** from the **cookies** received in the request and give you the Pydantic model you defined.

## Check the Docs

You can see the defined cookies in the docs UI at `/docs`:

<div class="screenshot">
<img src="/img/tutorial/cookie-param-models/image01.png">
</div>

   *
   * <p>When passed a key that is present in the map, {@code asMap().get(Object)} has the same
   * behavior as {@link #get}, returning a live collection. When passed a key that is not present,
   * however, {@code asMap().get(Object)} returns {@code null} instead of an empty collection.
   *