}
            }
        }

        if (member instanceof JApiField) {

            JApiField field = (JApiField) member
            CtField oldField = field.oldFieldOptional.get()
            CtField newField = field.newFieldOptional.get()

            def oldNullability = hasNullableAnnotation(oldField)
            def newNullability = hasNullableAnnotation(newField)

	for k := range mapValue {
		keys = append(keys, k)
	}
	sort.Strings(keys)

	for _, k := range keys {
		value := mapValue[k]
		if stmt.Schema != nil {
			if field := stmt.Schema.LookUpField(k); field != nil {
				k = field.DBName
			}
		}

		if v, ok := selectColumns[k]; (ok && v) || (!ok && !restricted) {
			values.Columns = append(values.Columns, clause.Column{Name: k})
			if len(values.Values) == 0 {

                """
                `username` string. The OAuth2 spec requires the exact field name
                `username`.
                """
            ),
        ],
        password: Annotated[
            str,
            Form(),
            Doc(
                """
                `password` string. The OAuth2 spec requires the exact field name
                `password".
                """
            ),
        ],

	// in Using IAM.
	//
	// Arn is a required field
	Arn string

	// A unique identifier that contains the role ID and the role session name of
	// the role that is being assumed. The role ID is generated by AWS when the
	// role is created.
	//
	// AssumedRoleId is a required field
	AssumedRoleID string `xml:"AssumeRoleId"`
	// contains filtered or unexported fields
}

  // level may borrow at any one time.
  // This field holds the ratio of that limit to the level's nominal
  // concurrency limit. When this field is non-nil, it must hold a
  // non-negative integer and the limit is calculated as follows.
  //
  // BorrowingCL(i) = round( NominalCL(i) * borrowingLimitPercent(i)/100.0 )
  //
  // The value of this field can be more than 100, implying that this

{* ../../docs_src/separate_openapi_schemas/tutorial001_py310.py ln[1:15] hl[14] *}

...then the `description` field will **not be required**. Because it has a default value of `None`.

### Input Model in Docs

You can confirm that in the docs, the `description` field doesn't have a **red asterisk**, it's not marked as required:

<div class="screenshot">
<img src="/img/tutorial/separate-openapi-schemas/image01.png">

```

////

//// 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"

 * container: this annotation is only effective on fields of the Mojo class itself, nested bean injection
 * requires Sisu or JSR330 annotations.
 *
 * @since 4.0.0
 */
@Experimental
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.METHOD})
@Inherited
public @interface Parameter {
    /**
     * name of the bean property used to get/set the field: by default, field name is used.

  // honor this field as long as the requested duration is not greater than the
  // maximum duration they will honor per the --cluster-signing-duration CLI
  // flag to the Kubernetes controller manager.
  //
  // Certificate signers may not honor this field for various reasons:
  //
  //   1. Old signer that is unaware of the field (such as the in-tree
  //      implementations prior to v1.22)

from typing import Annotated, Literal

from fastapi import FastAPI, Query
from pydantic import BaseModel, Field

app = FastAPI()


class FilterParams(BaseModel):
    limit: int = Field(100, gt=0, le=100)
    offset: int = Field(0, ge=0)
    order_by: Literal["created_at", "updated_at"] = "created_at"
    tags: list[str] = []


@app.get("/items/")
async def read_items(filter_query: Annotated[FilterParams, Query()]):