* AtomicInteger results in zero, we compareAndSet the value to zero; if that succeeds, we remove
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is
   * about to be removed, so this operation may remove it (often by replacing it with a new
   * AtomicInteger).
   */

  /** The number of occurrences of each element. */

  }

  // mutators (not supported)

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  // DoNotCall wants this to be final, but we want to override it to return more specific types.

	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")

///

### Path operation 関数

*path operation 関数*を `async def` の代わりに通常の `def` で宣言すると、(サーバーをブロックするので) 直接呼び出す代わりに外部スレッドプール (awaitされる) で実行されます。

 *
 * <ul>
 * <li><code>CallNamedPipe</code> A message-type pipe call that opens,
 * writes to, reads from, and closes the pipe in a single operation.
 * <li><code>TransactNamedPipe</code> A message-type pipe call that
 * writes to and reads from an existing pipe descriptor in one operation.
 * <li><code>CreateFile</code>, <code>ReadFile</code>,
 * <code>WriteFile</code>, and <code>CloseFile</code> A byte-type pipe can

	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")

FastAPIが実際にチェックしているのは、それが「呼び出し可能」（関数、クラス、その他なんでも）であり、パラメータが定義されているかどうかということです。

**FastAPI** の依存関係として「呼び出し可能なもの」を渡すと、その「呼び出し可能なもの」のパラメータを解析し、サブ依存関係も含めて、*path operation関数*のパラメータと同じように処理します。

それは、パラメータが全くない呼び出し可能なものにも適用されます。パラメータのない*path operation関数*と同じように。

そこで、上で紹介した依存関係の`common_parameters`を`CommonQueryParams`クラスに変更します:

```Python hl_lines="11 12 13 14 15"
{!../../docs_src/dependencies/tutorial002.py!}
```

			b := disk.AlignedBlock(SmallBlock)
			return &b
		},
	}
)

// WriteOnCloser implements io.WriteCloser and always
// executes at least one write operation if it is closed.
//
// This can be useful within the context of HTTP. At least
// one write operation must happen to send the HTTP headers
// to the peer.
type WriteOnCloser struct {
	io.Writer
	hasWritten bool
}

	return info, nil
}

// GetDriveStats returns IO stats of the drive by its major:minor
func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return IOStats{}, errors.New("operation unsupported")

│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

Let's say that now the file `main.py` with your **FastAPI** app has some other **path operations**.

It has a `GET` operation that could return an error.

It has a `POST` operation that could return several errors.

Both *path operations* require an `X-Token` header.

//// tab | Python 3.10+

```Python