return result
  }

  /** A hostname pattern and certificate hash for Certificate Pinning. */
  class Pin(pattern: String, pin: String) {
    /** A hostname like `example.com` or a pattern like `*.example.com` (canonical form). */
    val pattern: String

    /** Either `sha1` or `sha256`. */
    val hashAlgorithm: String

    /** The hash of the pinned certificate using [hashAlgorithm]. */

In this example, when the client requests an item by an ID that doesn't exist, raise an exception with a status code of `404`:

```Python hl_lines="11"
{!../../docs_src/handling_errors/tutorial001.py!}
```

### The resulting response

    "output": "ab--c.xn--zca"
  },
  {
    "input": "ab--c.ß",
    "output": "ab--c.xn--zca"
  },
  {
    "comment": "CheckJoiners is true",
    "input": "\u200D.example",
    "output": null
  },
  {
    "input": "xn--1ug.example",
    "output": null
  },
  {
    "comment": "CheckBidi is true",
    "input": "يa",
    "output": null
  },
  {
    "input": "xn--a-yoc",
    "output": null

It would also mean that if you get data from the `Request` object directly (for example, read the body) it won't be validated, converted or documented (with OpenAPI, for the automatic API user interface) by FastAPI.

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

```console
$ pip install python-multipart
```

///

/// note

This is supported since FastAPI version `0.113.0`. 🤓

///

## Pydantic Models for Forms

If you want to secure your API, there are several better things you can do, for example:

* Make sure you have well defined Pydantic models for your request bodies and responses.
* Configure any required permissions and roles using dependencies.
* Never store plaintext passwords, only password hashes.

import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link ListenableFuture} that supports fluent chains of operations. For example:
 *
 * <pre>{@code
 * ListenableFuture<Boolean> adminIsLoggedIn =
 *     FluentFuture.from(usersDatabase.getAdminUser())
 *         .transform(User::getId, directExecutor())

* `allow_origins` - Список источников, на которые разрешено выполнять кросс-доменные запросы. Например, `['https://example.org', 'https://www.example.org']`. Можно использовать `['*']`, чтобы разрешить любые источники.
* `allow_origin_regex` - Регулярное выражение для определения  источников, на которые разрешено выполнять кросс-доменные запросы. Например, `'https://.*\.example\.org'`.

* `allow_origins` - A list of origins that should be permitted to make cross-origin requests. E.g. `['https://example.org', 'https://www.example.org']`. You can use `['*']` to allow any origin.
* `allow_origin_regex` - A regex string to match against origins that should be permitted to make cross-origin requests. e.g. `'https://.*\.example\.org'`.

# Classes as Dependencies

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example

In the previous example, we were returning a `dict` from our dependency ("dependable"):

//// tab | Python 3.10+

```Python hl_lines="9"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="11"