DB.Migrator().DropTable(&Label{}, &Book{})
	if err := DB.AutoMigrate(&Label{}, &Book{}); err != nil {
		t.Fatalf("failed to migrate, got %v", err)
	}

	book := Book{
		Name: "my book",
		Labels: []Label{
			{Name: "region", Value: "emea"},
		},
	}

	DB.Create(&book)

	var result Book
	if err := DB.Preload("Labels").First(&result, book.ID).Error; err != nil {

{* ../../docs_src/header_param_models/tutorial002_an_py310.py hl[10] *}

Se um cliente tentar enviar alguns **cabeçalhos extra**, eles irão receber uma resposta de **erro**.

Por exemplo, se o cliente tentar enviar um cabeçalho `tool` com o valor `plumbus`, ele irá receber uma resposta de **erro** informando que o parâmetro do cabeçalho `tool` não é permitido:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",

		defer cancel()

		if _, err := GlobalKMS.GenerateKey(ctx, &kms.GenerateKeyRequest{AssociatedData: kms.Context{"healthcheck": ""}}); err != nil {
			switch r.Method {
			case http.MethodHead:
				apiErr := toAPIError(r.Context(), err)
				writeResponse(w, apiErr.HTTPStatusCode, nil, mimeNone)
			case http.MethodGet:
				writeErrorResponse(r.Context(), w, toAPIError(r.Context(), err), r.URL)
			}
			return
		}
	}

	m.Set(scannerVersionsScanned, float64(globalScannerMetrics.lifetime(scannerMetricApplyVersion)))

	dui, err := c.dataUsageInfo.Get()
	if err != nil {
		metricsLogIf(ctx, err)
	} else {
		m.Set(scannerLastActivitySeconds, time.Since(dui.LastUpdate).Seconds())
	}

	return nil

func metricsRequestAuthenticate(req *http.Request) (*xjwt.MapClaims, []string, bool, error) {
	token, err := jwtreq.AuthorizationHeaderExtractor.ExtractToken(req)
	if err != nil {
		if err == jwtreq.ErrNoTokenInRequest {
			return nil, nil, false, errNoAuthToken
		}
		return nil, nil, false, err
	}
	claims := xjwt.NewMapClaims()
	if err := xjwt.ParseWithClaims(token, claims, func(claims *xjwt.MapClaims) ([]byte, error) {

            if (!badFiles.empty) {
                System.err.println("Found bad files in merge commit $commit, run the listed commands:")
                badFiles.each {
                    System.err.println("git restore --source=master -SW -- '$it'")
                }
                System.err.println("And then amend the merge commit to remove all offending changes.")
                System.exit(1)

			if len(mm) != 1 {
				t.Errorf("%s: invalid errorcheck line:\n%s", fileline, line)
			} else if err := errors[fileline]; err == "" {
				t.Errorf("%s: missing error, want %s", fileline, all)
			} else if !strings.Contains(err, mm[0][1]) {
				t.Errorf("%s: wrong error for %s:\n%s", fileline, all, err)
			}
		} else {
			if errors[fileline] != "" {
				t.Errorf("unexpected error on %s: %v", fileline, errors[fileline])

				}
				db.scanIntoStruct(rows, reflectValue, values, fields, joinFields)
			}
		default:
			db.AddError(rows.Scan(dest))
		}
	}

	if err := rows.Err(); err != nil && err != db.Error {
		db.AddError(err)
	}

	if db.RowsAffected == 0 && db.Statement.RaiseErrorOnNotFound && db.Error == nil {
		db.AddError(ErrRecordNotFound)
	}

)

// loadMemoryMetrics - `MetricsLoaderFn` for node memory metrics.
func loadMemoryMetrics(ctx context.Context, m MetricValues, c *metricsCache) error {
	memMetrics, err := c.memoryMetrics.Get()
	if err != nil {
		metricsLogIf(ctx, err)
		return err
	}

	m.Set(memTotal, float64(memMetrics.Total))
	m.Set(memUsed, float64(memMetrics.Used))
	usedPerc := float64(memMetrics.Used) * 100 / float64(memMetrics.Total)

	return nil
}

func (UserWithCallback) AfterCreate(*gorm.DB) error {
	return nil
}

func TestCallback(t *testing.T) {
	user, err := schema.Parse(&UserWithCallback{}, &sync.Map{}, schema.NamingStrategy{})
	if err != nil {
		t.Fatalf("failed to parse user with callback, got error %v", err)
	}

	for _, str := range []string{"BeforeSave", "AfterCreate"} {