You will learn more about adding extra information later in the docs, when learning to declare examples.

/// warning

Extra keys passed to `Field` will also be present in the resulting OpenAPI schema for your application.
As these keys may not necessarily be part of the OpenAPI specification, some OpenAPI tools, for example [the OpenAPI validator](https://validator.swagger.io/), may not work with your generated schema.

   *
   * <p>See {@link java.util.Formatter} for a richer set of formatting capabilities.
   *
   * @param string the string which should appear at the end of the result
   * @param minLength the minimum length the resulting string must have. Can be zero or negative, in
   *     which case the input string is always returned.
   * @param padChar the character to insert at the beginning of the result until the minimum length
   *     is reached

In this example, when the client requests an item by an ID that doesn't exist, raise an exception with a status code of `404`:

{* ../../docs_src/handling_errors/tutorial001.py hl[11] *}

### The resulting response { #the-resulting-response }

If the client requests `http://example.com/items/foo` (an `item_id` `"foo"`), that client will receive an HTTP status code of 200, and a JSON response of:

```JSON
{
  "item": "The Foo Wrestlers"

   * BloomFilter} with false positive probability 3%.
   *
   * <p>Note that if the {@code Collector} receives significantly more elements than specified, the
   * resulting {@code BloomFilter} will suffer a sharp deterioration of its false positive
   * probability.
   *
   * <p>The constructed {@code BloomFilter} will be serializable if the provided {@code Funnel<T>}
   * is.
   *

If you open the automatic API docs, your extension will show up at the bottom of the specific *path operation*.

<img src="/img/tutorial/path-operation-advanced-configuration/image01.png">

And if you see the resulting OpenAPI (at `/openapi.json` in your API), you will see your extension as part of the specific *path operation* too:

```JSON hl_lines="22"
{
    "openapi": "3.1.0",
    "info": {
        "title": "FastAPI",

//
// Implements minimal S3 compatible ListMultipartUploads API. We do
// not support prefix based listing, this is a deliberate attempt
// towards simplification of multipart APIs.
// The resulting ListMultipartsInfo structure is unmarshalled directly as XML.

Then you create an instance of that class with some values and it will validate the values, convert them to the appropriate type (if that's the case) and give you an object with all the data.

And you get all the editor support with that resulting object.

An example from the official Pydantic docs:

//// tab | Python 3.10+

```Python
{!> ../../docs_src/python_types/tutorial011_py310.py!}
```

////

//// tab | Python 3.9+

 * <code>java.io.File</code> usage; a '/' at the beginning of the second
 * parameter will still use the server component of the first parameter. The
 * examples below illustrate the resulting URLs when this second constructor
 * argument is used.
 *
 * <table border="1">
 * <caption>Examples Of SMB URLs When Augmented With A Second Constructor Parameter</caption>
 * <tr >
 * <td colspan="3">

			},
		})
	}
}

type actionsAccountingFn func(oi ObjectInfo, sz, actualSz int64, sizeS *sizeSummary)

// applyActions will apply lifecycle checks on to a scanned item.
// The resulting size on disk will always be returned.
// The metadata will be compared to consensus on the object layer before any changes are applied.
// If no metadata is supplied, -1 is returned if no action is taken.

		a[i] = s[span.start:span.end:span.end]
	}

	return a
}

// Join concatenates the elements of s to create a new byte slice. The separator
// sep is placed between elements in the resulting slice.
func Join(s [][]byte, sep []byte) []byte {
	if len(s) == 0 {
		return []byte{}
	}
	if len(s) == 1 {
		// Just return a copy.
		return append([]byte(nil), s[0]...)
	}

	var n int