* 変数`prices`は`dict`であり:
    * この`dict`のキーは`str`型です。（つまり、各項目の名前）
    * この`dict`の値は`float`型です。（つまり、各項目の価格）

#### `Optional`

また、`Optional`を使用して、変数が`str`のような型を持つことを宣言することもできますが、それは「オプション」であり、`None`にすることもできます。

```Python hl_lines="1 4"
{!../../docs_src/python_types/tutorial009.py!}
```

ただの`str`の代わりに`Optional[str]`を使用することで、エディタは値が常に`str`であると仮定している場合に実際には`None`である可能性があるエラーを検出するのに役立ちます。

#### ジェネリック型

     * @param sessionId The session ID to filter by (optional).
     * @param queryBuilder The query builder for search criteria (optional).
     * @param from The starting index for pagination (optional).
     * @param size The maximum number of results to return (optional).
     * @param sortBuilders The sort builders for ordering results (optional).
     * @return The list of retrieved objects.
     */

 *
 * While [onReset] may occur at any time, the following callbacks are expected in order,
 * correlated by stream ID.
 *
 *  * [onRequest]
 *  * [onHeaders] (unless canceled)
 *  * [onData] (optional sequence of data frames)
 *
 * As a stream ID is scoped to a single HTTP/2 connection, implementations which target multiple
 * connections should expect repetition of stream IDs.
 *

        for (Object aSet : set) {
            Artifact artifact = (Artifact) aSet;
            System.out.println("Artifact: " + artifact.getDependencyConflictId() + " " + artifact.getVersion()
                    + " Optional=" + (artifact.isOptional() ? "true" : "false"));
            assertTrue(
                    artifact.getVersion().equals("1.0"), "Incorrect version for " + artifact.getDependencyConflictId());
        }
    }

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package http

import (
	"context"
	"net"
	"time"
)

// LookupHost is a function to make custom lookupHost for optional cached DNS requests
type LookupHost func(ctx context.Context, host string) (addrs []string, err error)

// DialContextWithLookupHost is a helper function which returns `net.DialContext` function.

        env:
          MYSQL_DATABASE: gorm
          MYSQL_USER: gorm
          MYSQL_PASSWORD: gorm
          MYSQL_RANDOM_ROOT_PASSWORD: "yes"
        ports:
          - 9910:3306
        options: >-
          --health-cmd "mysqladmin ping -ugorm -pgorm"
          --health-interval 10s
          --health-start-period 10s
          --health-timeout 5s
          --health-retries 10

    steps:

</div>

/// note | Nota

Quando você instala com `pip install "fastapi[standard]"`, ele vem com algumas dependências opcionais padrão, incluindo `fastapi-cloud-cli`, que permite fazer deploy na <a href="https://fastapicloud.com" class="external-link" target="_blank">FastAPI Cloud</a>.

Se você não quiser ter essas dependências opcionais, pode instalar `pip install fastapi` em vez disso.

## `dependencies` zum *Pfadoperation-Dekorator* hinzufügen { #add-dependencies-to-the-path-operation-decorator }

Der *Pfadoperation-Dekorator* erhält ein optionales Argument `dependencies`.

Es sollte eine `list`e von `Depends()` sein:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[19] *}

  /**
   * ```
   * Point ::= SEQUENCE {
   *   x [0] INTEGER OPTIONAL,
   *   y [1] INTEGER OPTIONAL
   * }
   * ```
   */
  data class Point(
    val x: Long?,
    val y: Long?,
  ) {
    companion object {
      val ADAPTER =
        Adapters.sequence(
          "Point",
          Adapters.INTEGER_AS_LONG.withTag(tag = 0L).optional(),
          Adapters.INTEGER_AS_LONG.withTag(tag = 1L).optional(),

## Add `dependencies` to the *path operation decorator* { #add-dependencies-to-the-path-operation-decorator }

The *path operation decorator* receives an optional argument `dependencies`.

It should be a `list` of `Depends()`:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[19] *}