```JSON
{"item_id":"foo"}
```

## Параметры пути с типами { #path-parameters-with-types }

Вы можете объявить тип параметра пути в функции, используя стандартные аннотации типов Python:

{* ../../docs_src/path_params/tutorial002_py39.py hl[7] *}

Здесь, `item_id` объявлен типом `int`.

 * the {@link ProjectBuilder} service.
 *
 * @since 4.0.0
 */
@Experimental
@Immutable
public interface ModelBuilderRequest extends RepositoryAwareRequest {

    /**
     * The possible request types for building a model.
     */
    enum RequestType {
        /**
         * The request is for building an initial model from a POM file in a project on the filesystem.
         */
        BUILD_PROJECT,
        /**

   *     different kind of exception, that exception itself. To avoid hiding bugs and other
   *     unrecoverable errors, callers should prefer more specific types, avoiding {@code
   *     Throwable.class} in particular.
   * @param fallback the {@link Function} to be called if the input fails with the expected

### 現代的なPython

FastAPIの機能はすべて、標準のPython 3.8型宣言に基づいています（Pydanticの功績）。新しい構文はありません。ただの現代的な標準のPythonです。

（FastAPIを使用しない場合でも）Pythonの型の使用方法について簡単な復習が必要な場合は、短いチュートリアル（[Python Types](python-types.md){.internal-link target=_blank}）を参照してください。

型を使用した標準的なPythonを記述します:

```Python
from datetime import date

from pydantic import BaseModel

# Declare a variable as a str

 *
 * <p>See the Guava User's Guide's <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#immutable-implementations">discussion
 * of the {@code Immutable*} types</a> for more information on the properties and guarantees
 * provided by this class.
 *
 * @author James Sexton
 * @author Jens Nyman
 * @param <N> Node parameter type
 * @param <V> Value parameter type
 * @since 20.0

				in.input = nil
				in.err = d.Err()
				in.dst <- all
			}
		}()
	}
}

// NewPReader - creates new parallel JSON reader using readCloser.
// Should only be used for LINES types.
func NewPReader(readCloser io.ReadCloser, args *ReaderArgs) *PReader {
	r := &PReader{
		args:       args,
		buf:        bufio.NewReaderSize(readCloser, jsonSplitSize*2),
		readCloser: readCloser,

/// note | Hinweis

Wenn Sie eine <a href="https://docs.pydantic.dev/latest/concepts/types/#unions" class="external-link" target="_blank">`Union`</a> definieren, listen Sie den spezifischeren Typ zuerst auf, gefolgt vom weniger spezifischen Typ. Im Beispiel unten steht `PlaneItem` vor `CarItem` in `Union[PlaneItem, CarItem]`.

/// note | Примечание

При объявлении <a href="https://docs.pydantic.dev/latest/concepts/types/#unions" class="external-link" target="_blank">`Union`</a>, сначала указывайте наиболее детальные типы, затем менее детальные. В примере ниже более детальный `PlaneItem` стоит перед `CarItem` в `Union[PlaneItem, CarItem]`.

///

       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */
      private static final Set<WeakReference<Class<? extends Exception>>> validClasses =
          new CopyOnWriteArraySet<>();

      @Override

  private val typeHintStack = mutableListOf<Any?>()

  /**
   * The type hint for the current object. Used to pick adapters based on other fields, such as
   * in extensions which have different types depending on their extension ID.
   */
  var typeHint: Any?
    get() = typeHintStack.lastOrNull()
    set(value) {
      typeHintStack[typeHintStack.size - 1] = value
    }