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

## Use Case

Let's start with an example **use case** and then see how to solve it with this.

Let's imagine that you have some **machine learning models** that you want to use to handle requests. 🤖

  optional k8s.io.apimachinery.pkg.apis.meta.v1.GroupVersionKind kind = 2;

  // Resource is the fully-qualified resource being requested (for example, v1.pods)
  optional k8s.io.apimachinery.pkg.apis.meta.v1.GroupVersionResource resource = 3;

  // SubResource is the subresource being requested, if any (for example, "status" or "scale")
  // +optional

from ...utils import needs_py310


@pytest.fixture(name="client")
def get_client():
    from docs_src.schema_extra_example.tutorial004_an_py310 import app

    client = TestClient(app)
    return client


# Test required and embedded body parameters with no bodies sent
@needs_py310
def test_post_body_example(client: TestClient):
    response = client.put(
        "/items/5",
        json={
            "name": "Foo",

    open fun encode(codePoint: Int): String {
      throw UnsupportedOperationException()
    }
  }

  enum class Component {
    USER {
      override fun urlString(value: String): String = "http://$value@example.com/"

      override fun encodedValue(url: HttpUrl): String = url.encodedUsername

      override operator fun set(
        builder: HttpUrl.Builder,
        value: String,
      ) {

### Multiple Applications

In the same server (or servers), there could be **multiple applications**, for example, other API programs or a database.

Only one process can be handling the specific IP and port (the TLS Termination Proxy in our example) but the other applications/processes can be running on the server(s) too, as long as they don't try to use the same **combination of public IP and port**.

* Convert the copied model to something that can be stored in your DB (for example, using the `jsonable_encoder`).
    * This is comparable to using the model's `.model_dump()` method again, but it makes sure (and converts) the values to data types that can be converted to JSON, for example, `datetime` to `str`.
* Save the data to your DB.
* Return the updated model.

=== "Python 3.10+"

    Read more about it in the
    [FastAPI docs for Simple OAuth2 with Password and Bearer](https://fastapi.tiangolo.com/tutorial/security/simple-oauth2/).

    ## Example

    ```python
    from typing import Annotated

    from fastapi import Depends, FastAPI
    from fastapi.security import OAuth2PasswordRequestForm

    app = FastAPI()


    @app.post("/login")

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder`

Let's imagine that you have a database `fake_db` that only receives JSON compatible data.

For example, it doesn't receive `datetime` objects, as those are not compatible with JSON.

FastAPI converts the configurations to **JSON** to make them compatible with JavaScript, as that's what Swagger UI needs.

## Disable Syntax Highlighting

For example, you could disable syntax highlighting in Swagger UI.

Without changing the settings, syntax highlighting is enabled by default:

<img src="/img/tutorial/extending-openapi/image02.png">