as the support for external CAs is more mature than external discovery servers. This supports some additional
configuration, a `CredentialFetcher` which allows fetching a token from places other than a file (for example, a local
metadata server), and a `TokenExchanger` which allows exchanging a token for another form to match the CA server requirements.

  // As Kubernetes 1.15 doesn't support this field, drivers can only support one mode when
  // deployed on such a cluster and the deployment determines which mode that is, for example
  // via a command line parameter of the driver.
  //
  // This field is immutable.
  //
  // +optional
  optional bool podInfoOnMount = 2;

 *       Future} is "completed" even if it is cancelled while its underlying work continues on a
 *       thread, an RPC, etc. The {@code Future} is also "completed" if it fails "early" -- for
 *       example, if the deadline expires on a {@code Future} returned from {@link
 *       Futures#withTimeout} while the {@code Future} it wraps continues its underlying work. So

   * 'affect' a bit(j) in the output if two inputs, identical but for bit(i), will differ at output
   * bit(j) about half the time
   *
   * <p>Funneling is pretty simple to detect. The key idea is to find example keys which
   * unequivocally demonstrate that funneling cannot be occurring. This is done bit-by-bit. For each
   * input bit(i) and output bit(j), two pairs of keys must be found with all bits identical except

```Python hl_lines="11"
{!../../docs_src/handling_errors/tutorial001.py!}
```

### レスポンス結果

クライアントが`http://example.com/items/foo`（`item_id` `"foo"`）をリクエストすると、HTTPステータスコードが200で、以下のJSONレスポンスが返されます:

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

しかし、クライアントが`http://example.com/items/bar`（存在しない`item_id` `"bar"`）をリクエストした場合、HTTPステータスコード404（"not found"エラー）と以下のJSONレスポンスが返されます:

```JSON
{

     licenses, a licensor grants the public permission to use the
     licensed material under specified terms and conditions. If
     the licensor's permission is not necessary for any reason--for
     example, because of any applicable exception or limitation to
     copyright--then that use is not regulated by the license. Our
     licenses grant only permissions under copyright and certain

   * convenient.
   *
   * <p>By default, a {@code Builder} will generate maps that iterate over entries in the order they
   * were inserted into the builder, equivalently to {@code LinkedHashMap}. For example, in the
   * above example, {@code WORD_TO_INT.entrySet()} is guaranteed to iterate over the entries in the
   * order {@code "one"=1, "two"=2, "three"=3}, and {@code keySet()} and {@code values()} respect

  // +listType=set
  // Required.
  repeated string verbs = 1;

  // `nonResourceURLs` is a set of url prefixes that a user should have access to and may not be empty.
  // For example:
  //   - "/healthz" is legal
  //   - "/hea*" is illegal
  //   - "/hea" is legal but matches nothing
  //   - "/hea/*" also matches nothing
  //   - "/healthz/*" matches all per-component health checks.

 * itself is reclaimable. <i>Weak</i> means that locks/semaphores are created lazily, and they are
 * allowed to be reclaimed if nobody is holding on to them. This is useful, for example, if one
 * wants to create a {@code Striped<Lock>} of many locks, but worries that in most cases only a
 * small portion of these would be in use.
 *

 * initiated via other mechanisms do not impact the correctness of its methods. For example, if the
 * services are started by some mechanism besides {@link #startAsync}, the listeners will be invoked
 * when appropriate and {@link #awaitHealthy} will still work as expected.
 *
 * <p>Here is a simple example of how to use a {@code ServiceManager} to start a server.
 *
 * <pre>{@code
 * class Server {