{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...como `description` e `tax` são opcionais (com um valor padrão de `None`), esse JSON "`object`" também é válido:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Declare como um parâmetro { #declare-it-as-a-parameter }

func (ct ColumnType) DatabaseTypeName() string {
	if ct.DataTypeValue.Valid {
		return ct.DataTypeValue.String
	}
	return ct.SQLColumnType.DatabaseTypeName()
}

// ColumnType returns the database type of the column. like `varchar(16)`
func (ct ColumnType) ColumnType() (columnType string, ok bool) {
	return ct.ColumnTypeValue.String, ct.ColumnTypeValue.Valid
}

// PrimaryKey returns the column is primary key or not.

		// passing in valid bucket names.
		{"lol", true},
		{"1-this-is-valid", true},
		{"1-this-too-is-valid-1", true},
		{"this.works.too.1", true},
		{"1234567", true},
		{"123", true},
		{"s3-eu-west-1.amazonaws.com", true},
		{"ideas-are-more-powerful-than-guns", true},
		{"testbucket", true},
		{"1bucket", true},
		{"bucket1", true},
		{"$this-is-not-valid-too", true},
		{"contains-$-dollar", true},

				strings.Join([]string{
					// generating a valid credential.
					generateCredentialStr(
						"access key",
						sampleTimeStr,
						"us-west-1",
						"s3",
						"aws4_request"),
					// valid SignedHeader.
					"SignedHeaders=host;x-amz-content-sha256;x-amz-date",
					// valid Signature field.
					// a valid signature is of form "Signature="
					"Signature=abcd",
				}, ","),

func (c *StandardClaims) SetAccessKey(accessKey string) {
	c.Subject = accessKey
	c.AccessKey = accessKey
}

// Valid - implements https://godoc.org/github.com/golang-jwt/jwt#Claims compatible
// claims interface, additionally validates "accessKey" fields.
func (c *StandardClaims) Valid() error {
	if err := c.StandardClaims.Valid(); err != nil {
		return err
	}

	if c.AccessKey == "" && c.Subject == "" {

		Name:     sql.NullString{String: "name", Valid: true},
		Gender:   &sql.NullString{String: "M", Valid: true},
		Age:      sql.NullInt64{Int64: 18, Valid: true},
		Male:     sql.NullBool{Bool: true, Valid: true},
		Height:   sql.NullFloat64{Float64: 1.8888, Valid: true},
		Birthday: sql.NullTime{Time: time.Now(), Valid: true},
		Allergen: NullString{sql.NullString{String: "Allergen", Valid: true}},
		Password: EncryptedData("pass1"),

# Hibernate Validator
# -------------------
constraints.CreditCardNumber.message = {item} est un numéro de carte de crédit non valide.
constraints.EAN.message = {item} est un code-barres {type} non valide.
constraints.Email.message = {item} n'est pas une adresse e-mail valide.
constraints.Length.message = La longueur de {item} doit être comprise entre {min} et {max}.

func (n DeletedAt) Value() (driver.Value, error) {
	if !n.Valid {
		return nil, nil
	}
	return n.Time, nil
}

func (n DeletedAt) MarshalJSON() ([]byte, error) {
	if n.Valid {
		return json.Marshal(n.Time)
	}
	return json.Marshal(nil)
}

func (n *DeletedAt) UnmarshalJSON(b []byte) error {
	if string(b) == "null" {
		n.Valid = false
		return nil
	}
	err := json.Unmarshal(b, &n.Time)

app = FastAPI()


class Item(BaseModel):
    name: str = Field(alias="aliased_name")
    price: float | None = None
    owner_ids: list[int] | None = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return Item(aliased_name="valid", price=1.0)


@app.get("/items/coerce", response_model=Item)
def get_coerce():
    return Item(aliased_name="coerce", price="1.0")

		deletedAt     = mytime(time.Now())
		isAdmin       = mybool(false)
		user          = AdvancedDataTypeUser{
			ID:           sql.NullInt64{Int64: 10, Valid: true},
			Name:         &sql.NullString{String: name, Valid: true},
			Birthday:     sql.NullTime{Time: time.Now(), Valid: true},
			RegisteredAt: mytime(time.Now()),
			DeletedAt:    &deletedAt,
			Active:       mybool(true),
			Admin:        &isAdmin,
		}