* selects a particular version, and downloads the artifact into the local repository.</p>
 *
 * <p>{@link org.apache.maven.api.Node} is the main output of the <dfn>dependency collection</dfn> process.
 * It's a node in the dependency graph and contains a {@code Dependency} instance. The {@code Dependency} instances are the outputs of the

## レスポンスモデルのエンコーディングパラメータ

レスポンスモデルにはデフォルト値を設定することができます:

{* ../../docs_src/response_model/tutorial004.py hl[11,13,14] *}

* `description: str = None`は`None`がデフォルト値です。
* `tax: float = 10.5`は`10.5`がデフォルト値です。
* `tags: List[str] = []` は空のリスト（`[]`）がデフォルト値です。

しかし、実際に保存されていない場合には結果からそれらを省略した方が良いかもしれません。

`Optional[Something]` là một cách viết ngắn gọn của `Union[Something, None]`, chúng là tương đương nhau.

Điều này cũng có nghĩa là trong Python 3.10, bạn có thể sử dụng `Something | None`:

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

#### `Optional`

`Optional` bir değişkenin `str`gibi bir tipi olabileceğini ama isteğe bağlı olarak tipinin `None` olabileceğini belirtir:

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

`str` yerine `Optional[str]` kullanmak editorün bu değerin her zaman `str` tipinde değil bazen `None` tipinde de olabileceğini belirtir ve hataları tespit etmemizde yardımcı olur.

#### Generic tipler

      }
    }
    return current;
  }

  /**
   * Returns the unique least value of type {@code C} that is greater than {@code value}, or {@code
   * null} if none exists. Inverse operation to {@link #previous}.
   *
   * @param value any value of type {@code C}
   * @return the least value greater than {@code value}, or {@code null} if {@code value} is {@code
   *     maxValue()}

                }
            }
            if (this.domain_guid.node == null) {
                if (_domain_guid_nodes < 0 || _domain_guid_nodes > 0xFFFF) {
                    throw new NdrException(NdrException.INVALID_CONFORMANCE);
                }
                this.domain_guid.node = new byte[_domain_guid_nodes];
            }
            _src = _src.derive(_domain_guid_nodei);

    }

    @Override
    public CharMatcher negate() {
      return none();
    }
  }

  /** Implementation of {@link #none()}. */
  private static final class None extends NamedFastMatcher {

    static final CharMatcher INSTANCE = new None();

    private None() {
      super("CharMatcher.none()");
    }

    @Override
    public boolean matches(char c) {

{* ../../docs_src/path_params_numeric_validations/tutorial001_an_py310.py hl[10] *}

/// note | Nota

Un parámetro de path siempre es requerido ya que tiene que formar parte del path. Incluso si lo declaras con `None` o le asignas un valor por defecto, no afectará en nada, siempre será requerido.

///

## Ordena los parámetros como necesites

/// tip | Consejo

```

`Optional[str]` ব্যবহার করা মানে হল শুধু `str` নয়, এটি হতে পারে `None`-ও, যা আপনার এডিটরকে সেই ত্রুটিগুলি শনাক্ত করতে সাহায্য করবে যেখানে আপনি ধরে নিচ্ছেন যে একটি মান সবসময় `str` হবে, অথচ এটি `None`-ও হতে পারেও।

`Optional[Something]` মূলত `Union[Something, None]`-এর একটি শর্টকাট, এবং তারা সমতুল্য।

এর মানে হল, Python 3.10-এ, আপনি টাইপগুলির ইউনিয়ন ঘোষণা করতে `Something | None` ব্যবহার করতে পারেন:

//// tab | Python 3.10+

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//