* complete}. If the computation has already completed when the listener is added, the listener will
 * execute immediately.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/ListenableFutureExplained">{@code
 * ListenableFuture}</a>.
 *
 * <p>This class is GWT-compatible.
 *
 * <h3>Purpose</h3>
 *

مثلاً می‌تونی یه فایل `main.py` داشته باشی با:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip

آرگومان دوم <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> مقدار پیش‌فرضیه که برمی‌گردونه.

اگه ندی، به‌صورت پیش‌فرض `None` هست، اینجا ما `"World"` رو به‌عنوان مقدار پیش‌فرض گذاشتیم.

///

## Sobrescrevendo os padrões

Com as informações acima, você pode usar a mesma função utilitária para gerar o esquema OpenAPI e sobrescrever cada parte que precisar.

Por exemplo, vamos adicionar <a href="https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo" class="external-link" target="_blank">Extensão OpenAPI do ReDoc para incluir um logo personalizado</a>.

### **FastAPI** Normal

////

/// info

💡 🌖 🔃 <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic, ✅ 🚮 🩺</a>.

///

**FastAPI** 🌐 ⚓️ 🔛 Pydantic.

👆 🔜 👀 📚 🌅 🌐 👉 💡 [🔰 - 👩‍💻 🦮](tutorial/index.md){.internal-link target=_blank}.

/// tip

///

////

//// tab | Pydantic v1

{* ../../docs_src/settings/app03_an/config_pv1.py hl[9:10] *}

/// tip

```

</div>

صفحه مستندات را در آدرس <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a> باز کنید.

اسناد API خودکار برنامه اصلی را مشاهده خواهید کرد که فقط شامل path operations خود می شود:

<img src="/img/tutorial/sub-applications/image01.png">

    nanos.addAndGet(nanoseconds);
    return this;
  }

  /**
   * Advances the ticker value by {@code duration}.
   *
   * @since 33.1.0 (but since 28.0 in the JRE <a
   *     href="https://github.com/google/guava#guava-google-core-libraries-for-java">flavor</a>)
   */
  @GwtIncompatible
  @J2ktIncompatible
  @CanIgnoreReturnValue

# 🔬 *️⃣

👆 💪 ⚙️ 🎏 `TestClient` 💯*️⃣.

👉, 👆 ⚙️ `TestClient` `with` 📄, 🔗*️⃣:

{* ../../docs_src/app_testing/tutorial002.py hl[27:31] *}

/// note

🌅 ℹ, ✅ 💃 🧾 <a href="https://www.starlette.io/testclient/#testing-websocket-sessions" class="external-link" target="_blank">🔬 *️⃣ </a>.

<h3 id="more">Additional Mechanisms</h3>

<p>
The <code>sync</code> package provides additional synchronization abstractions,
including <a href="/pkg/sync/#Cond">condition variables</a>,
<a href="/pkg/sync/#Map">lock-free maps</a>,
<a href="/pkg/sync/#Pool">allocation pools</a>,
and
<a href="/pkg/sync/#WaitGroup">wait groups</a>.
The documentation for each of these specifies the guarantees it
makes concerning synchronization.
</p>

Bu işlem için, `TestClient`'ı bir `with` ifadesinde kullanarak WebSocket'e bağlanabilirsiniz:

{* ../../docs_src/app_testing/tutorial002.py hl[27:31] *}

/// note | Not

Daha fazla detay için Starlette'in <a href="https://www.starlette.io/staticfiles/" class="external-link" target="_blank">Websockets'i Test Etmek</a> dokümantasyonunu inceleyin.