///

This will let **FastAPI** know that this parameter is required.

### Required, can be `None`

You can declare that a parameter can accept `None`, but that it's still required. This would force clients to send a value, even if the value is `None`.

To do that, you can declare that `None` is a valid type but still use `...` as the default:

//// tab | Python 3.10+

```Python hl_lines="9"

In this case, it would use the certificate for `someapp.example.com`.

<img src="/img/deployment/https/https03.svg">

The client already **trusts** the entity that generated that TLS certificate (in this case Let's Encrypt, but we'll see about that later), so it can **verify** that the certificate is valid.

    ]
)


@app.get("/foo")
def foo():
    return {"message": "Hello World"}


client = TestClient(app)


def test_app():
    response = client.get("/foo")
    assert response.status_code == 200, response.text


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {

  private void run() {
    OkHttpClient client = new OkHttpClient.Builder()
        .readTimeout(0,  TimeUnit.MILLISECONDS)
        .build();

    Request request = new Request.Builder()
        .url("ws://echo.websocket.org")
        .build();
    client.newWebSocket(request, this);

    // Trigger shutdown of the dispatcher's executor so this process exits immediately.
    client.dispatcher().executorService().shutdown();
  }

from fastapi.testclient import TestClient

from docs_src.configure_swagger_ui.tutorial002 import app

client = TestClient(app)


def test_swagger_ui():
    response = client.get("/docs")
    assert response.status_code == 200, response.text
    assert (
        '"syntaxHighlight": false' not in response.text
    ), "not used parameters should not be included"
    assert (
        '"syntaxHighlight.theme": "obsidian"' in response.text

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/kubernetes"
)

// Use UUID of kube-system Namespace as unique identifier for cluster.
// (see https://docs.google.com/document/d/1F__vEKeI41P7PPUCMM9PVPYY34pyrvQI5rbTJVnS5c4)
func clusterUID(client kubernetes.Interface) (types.UID, error) {
	kubeSystem, err := client.CoreV1().Namespaces().Get(context.TODO(), "kube-system", metav1.GetOptions{})
	if err != nil {

import okhttp3.Protocol
import okhttp3.Request

object ExternalHttp2Example {
  @JvmStatic
  fun main(args: Array<String>) {
    val client =
      OkHttpClient.Builder()
        .protocols(listOf(Protocol.HTTP_2, Protocol.HTTP_1_1))
        .build()
    val call =
      client.newCall(
        Request.Builder()
          .url("https://www.google.ca/")
          .build(),
      )
    val response = call.execute()

@app.post("/form/")
def post_form(username: Annotated[str, Form()]):
    return username


client = TestClient(app)


def test_single_form_field():
    response = client.post("/form/", data={"username": "Rick"})
    assert response.status_code == 200, response.text
    assert response.json() == "Rick"


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

    return {"msg": "Status overwritten", "id": id}


client = TestClient(app)


def test_dependency_set_status_code():
    response = client.delete("/1")
    assert response.status_code == 400 and response.content
    assert response.json() == {"msg": "Status overwritten", "id": 1}


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

@app.post("/foo")
def foo(items: Items):
    return items.items


client = TestClient(app)


def test_additional_properties_post():
    response = client.post("/foo", json={"items": {"foo": 1, "bar": 2}})
    assert response.status_code == 200, response.text
    assert response.json() == {"foo": 1, "bar": 2}


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text