```

////

//// tab | Python 3.8+

```Python hl_lines="15-23"
{!> ../../docs_src/schema_extra_example/tutorial001.py!}
```

////

这些额外的信息将按原样添加到输出的JSON模式中。

## `Field` 的附加参数

在 `Field`, `Path`, `Query`, `Body` 和其他你之后将会看到的工厂函数，你可以为JSON 模式声明额外信息，你也可以通过给工厂函数传递其他的任意参数来给JSON 模式声明额外信息，比如增加 `example`:

//// tab | Python 3.10+

```Python hl_lines="2  8-11"

	// Officially, the name and comment fields are supposed to be encoded
	// in CP-437 (which is mostly compatible with ASCII), unless the UTF-8
	// flag bit is set. However, there are several problems:
	//
	//	* Many ZIP readers still do not support UTF-8.
	//	* If the UTF-8 flag is cleared, several readers simply interpret the
	//	name and comment fields as whatever the local system encoding is.
	//

    extends AggregateFuture<V, C> {
  /*
   * We access this field racily but safely. For discussion of a similar situation, see the comments
   * on the fields of TimeoutFuture. This field is slightly different from the fields discussed
   * there: cancel() never reads this field, only writes to it. That makes the race here completely
   * harmless, rather than just 99.99% harmless.
   */

			// incorrectly believed that the old GNU format had a prefix field.
			// This is wrong and leads to an output file that mangles the
			// atime and ctime fields, which are often left unused.
			//
			// In order to continue reading tar files created by former, buggy
			// versions of Go, we skeptically parse the atime and ctime fields.
			// If we are unable to parse them and the prefix field looks like

}

// SetAccessKey sets access key as jwt subject and custom
// "accessKey" field.
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 {

func (z *xlMetaDataDirDecoder) DecodeMsg(dc *msgp.Reader) (err error) {
	var field []byte
	_ = field
	var zb0001 uint32
	zb0001, err = dc.ReadMapHeader()
	if err != nil {
		err = msgp.WrapError(err)
		return
	}
	var zb0001Mask uint8 /* 1 bits */
	_ = zb0001Mask
	for zb0001 > 0 {
		zb0001--
		field, err = dc.ReadMapKeyPtr()
		if err != nil {
			err = msgp.WrapError(err)
			return
		}

	// Iterate over policy conditions and check them against received form fields
	for _, policy := range postPolicyForm.Conditions.Policies {
		// Form fields names are in canonical format, convert conditions names
		// to canonical for simplification purpose, so `$key` will become `Key`
		formCanonicalName := http.CanonicalHeaderKey(strings.TrimPrefix(policy.Key, "$"))
		// Operator for the current policy condition
		op := policy.Operator

    delegate.addListener(fire, directExecutor());
    return result;
  }

  /*
   * Memory visibility of these fields. There are two cases to consider.
   *
   * 1. visibility of the writes to these fields to Fire.run:
   *
   * The initial write to delegateRef is made definitely visible via the semantics of

}

// ParseUniqueConstraints parse schema unique constraints
func (schema *Schema) ParseUniqueConstraints() map[string]UniqueConstraint {
	uniques := make(map[string]UniqueConstraint)
	for _, field := range schema.Fields {
		if field.Unique {
			name := schema.namer.UniqueName(schema.Table, field.DBName)
			uniques[name] = UniqueConstraint{Name: name, Field: field}
		}
	}
	return uniques

    /**
     * Set a field with the specified date. If the field is not found, it is added. If the field is
     * found, the existing values are replaced.
     */
    operator fun set(
      name: String,
      value: Date,
    ) = set(name, value.toHttpDateString())

    /**
     * Set a field with the specified instant. If the field is not found, it is added. If the field