from typing import Union


def process_item(item: Union[int, str]):

            "msg": "value is not a valid integer",
            "type": "type_error.integer"
        }
    ]
}
```

これは、パスパラメータ `item_id` が `int` ではない値 `"foo"` だからです。

<a href="http://127.0.0.1:8000/items/4.2" class="external-link" target="_blank">http://127.0.0.1:8000/items/4.2</a> で見られるように、intのかわりに `float` が与えられた場合にも同様なエラーが表示されます。

/// check | "確認"

したがって、Pythonの型宣言を使用することで、**FastAPI**はデータのバリデーションを行います。

  }

  private static void runTestFuzzyCompare(int toleranceIndex) {
    double tolerance = get(TOLERANCE_CANDIDATES, toleranceIndex);
    for (double a : ALL_DOUBLE_CANDIDATES) {
      for (double b : ALL_DOUBLE_CANDIDATES) {
        int expected = DoubleMath.fuzzyEquals(a, b, tolerance) ? 0 : Double.compare(a, b);
        int actual = DoubleMath.fuzzyCompare(a, b, tolerance);

   * in which it will attempt to cancel itself.
   *
   * <p>An example use of this method is to convert a serializable object returned from an RPC into
   * a POJO.
   *
   * <p>This method is similar to {@link java.util.concurrent.CompletableFuture#thenApply} and
   * {@link java.util.concurrent.CompletableFuture#thenApplyAsync}. It can also serve some of the

    private static final int MAX_INTITEM_LENGTH = 9;

    private static final int MAX_LONGITEM_LENGTH = 18;

    private String value;

    private String canonical;

    private ListItem items;

    private interface Item {
        int INT_ITEM = 3;
        int LONG_ITEM = 4;
        int BIGINTEGER_ITEM = 0;
        int STRING_ITEM = 1;
        int LIST_ITEM = 2;
        int COMBINATION_ITEM = 5;

     explicitly and finally terminates Your grants, and (b) on an ongoing basis,
     if such Contributor fails to notify You of the non-compliance by some
     reasonable means prior to 60 days after You have come back into compliance.
     Moreover, Your grants from a particular Contributor are reinstated on an
     ongoing basis if such Contributor notifies You of the non-compliance by

     explicitly and finally terminates Your grants, and (b) on an ongoing
     basis, if such Contributor fails to notify You of the non-compliance by
     some reasonable means prior to 60 days after You have come back into
     compliance. Moreover, Your grants from a particular Contributor are
     reinstated on an ongoing basis if such Contributor notifies You of the
     non-compliance by some reasonable means, this is the first time You have

        File dir = null;
        final URL url = getResource(path);
        if ("file".equals(url.getProtocol())) {
            final int num = path.split("/").length;
            dir = new File(getFileName(url));
            for (int i = 0; i < num; ++i) {
                dir = dir.getParentFile();
            }
        } else {
            dir = new File(JarFileUtil.toJarFilePath(url));
        }

def get_name_with_age(name: str, age: int):
    name_with_age = name + " is this old: " + str(age)

Ele também declara novamente `id: int`. Ao fazer isso, estamos fazendo um **contrato** com os clientes da API, para que eles possam sempre esperar que o `id` estará lá e será um `int` (nunca será `None`).

/// tip | Dica