## Ajouter une tâche d'arrière-plan

Dans votre *fonction de chemin*, passez votre fonction de tâche à l'objet de type `BackgroundTasks` (`background_tasks` ici) grâce à la méthode `.add_task()` :


{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}

`.add_task()` reçoit comme arguments :

* Une fonction de tâche à exécuter en arrière-plan (`write_notification`).

C'est un programme très simple.

Mais maintenant imaginez que vous l'écriviez de zéro.

À un certain point vous auriez commencé la définition de la fonction, vous aviez les paramètres prêts.

Mais vous aviez besoin de "cette méthode qui convertit la première lettre en majuscule".

Était-ce `upper` ? `uppercase` ? `first_uppercase` ? `capitalize` ?

Vous essayez donc d'utiliser le vieil ami du programmeur, l'auto-complétion de l'éditeur.

// factory receiver.  This constructor will normalize the username, password
// and authzID via the SASLprep algorithm, as recommended by RFC-5802.  If
// SASLprep fails, the method returns an error.
func (x *XDGSCRAMClient) Begin(userName, password, authzID string) (err error) {
	x.Client, err = x.NewClient(userName, password, authzID)
	if err != nil {
		return err
	}

        <field xdoc.separator="blank">
          <name>servers</name>
          <version>1.0.0+</version>
          <description>
            Configuration of server-specific settings, mainly authentication
            method. This allows configuration of authentication on a per-server
            basis.
          </description>
          <association>
            <type>Server</type>
            <multiplicity>*</multiplicity>

        return projects.stream().map(MavenProject::getFile).anyMatch(request.getPom()::equals);
    }

    /**
     * This method finds out whether collecting projects failed because of the following scenario:
     * - A multi-module project containing a module which is a plugin and another module which depends on it.

			t.Fatalf("Test %d: got %v expected %v", i+1, actual, tc)
		}
	}
}

// TestRestoreObjOnDisk tests restoreObjStatus' OnDisk method
func TestRestoreObjOnDisk(t *testing.T) {
	testCases := []struct {
		restoreStatus restoreObjStatus
		ondisk        bool
	}{
		{
			// restore in progress
			restoreStatus: ongoingRestoreObj(),

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package etag

import (
	"context"
	"crypto/md5"
	"fmt"
	"hash"
	"io"
)

// Tagger is the interface that wraps the basic ETag method.
type Tagger interface {
	ETag() ETag
}

type wrapReader struct {
	io.Reader
	Tagger
}

var _ Tagger = wrapReader{} // compiler check

// ETag returns the ETag of the underlying Tagger.

		panic(err)
	}

	time.Sleep(time.Duration(b[0]) * time.Millisecond)

	if target.sendErr {
		return errors.New("send error")
	}

	return nil
}

// SendFromStore - interface compatible method does no-op.
func (target *ExampleTarget) SendFromStore(_ store.Key) error {
	return nil
}

func (target ExampleTarget) Close() error {
	if target.closeErr {
		return errors.New("close error")
	}

Mas, se por algum motivo seus clientes dependem do comportamento antigo, você pode voltar a ele sobrescrevendo o método `make_not_authenticated_error` nas suas classes de segurança.

Por exemplo, você pode criar uma subclasse de `HTTPBearer` que retorne um erro `403 Forbidden` em vez do erro padrão `401 Unauthorized`:

def test_cors():
    client = TestClient(app)
    # Test pre-flight response
    headers = {
        "Origin": "https://localhost.tiangolo.com",
        "Access-Control-Request-Method": "GET",
        "Access-Control-Request-Headers": "X-Example",
    }
    response = client.options("/", headers=headers)
    assert response.status_code == 200, response.text
    assert response.text == "OK"
    assert (