## Install `WebSockets`

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and install `websockets`:

<div class="termy">

```console
$ pip install websockets

---> 100%
```

</div>

## WebSockets client

### In production

```

</div>

**強烈建議**你編寫或複製程式碼、進行修改並在本地端運行。

在編輯器中使用它，才能真正體會到 FastAPI 的好處，可以看到你只需編寫少量程式碼，以及所有的型別檢查、自動補齊等功能。

---

## 安裝 FastAPI

第一步是安裝 FastAPI。

確保你建立一個[虛擬環境](../virtual-environments.md){.internal-link target=_blank}，啟用它，然後**安裝 FastAPI**：

<div class="termy">

```console
$ pip install "fastapi[standard]"

---> 100%
```

</div>

/// note

    if (!enabled_) {
      return absl::OkStatus();
    }
    if (first_call_) {
      first_call_ = false;
      return absl::OkStatus();
    }
    return tensorflow::errors::Internal("Graph pass runs for more than once!");
  }

 private:
  bool first_call_ = true;
};

// After the graph pass is registered, it takes effect globally and can affect

отличным вариантом (среди многих других) для разработки веб-API и приложений
в области дата-сайенс / машинного обучения.

Как добиться такого параллелизма в эксплуатации описано в разделе [Развёртывание](deployment/index.md){.internal-link target=_blank}.

## `async` и `await`

В современных версиях Python разработка асинхронного кода реализована очень интуитивно.

import okhttp3.TestUtil.awaitGarbageCollection
import okhttp3.internal.DoubleInetAddressDns
import okhttp3.internal.RecordingOkAuthenticator
import okhttp3.internal.USER_AGENT
import okhttp3.internal.addHeaderLenient
import okhttp3.internal.closeQuietly
import okhttp3.internal.http.HTTP_EARLY_HINTS
import okhttp3.internal.http.HTTP_PROCESSING
import okhttp3.internal.http.RecordingProxySelector

                    valid, that would mean a violation of the contract with the client,
                    so it's an error from the API developer. So, FastAPI will raise an
                    error and return a 500 error code (Internal Server Error).

                Read more about it in the
                [FastAPI docs for Response Model](https://fastapi.tiangolo.com/tutorial/response-model/).
                """
            ),

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.idn

import okio.Buffer
import okio.ByteString.Companion.encodeUtf8

/**
 * An [RFC 3492] punycode decoder for converting ASCII to Unicode domain name labels. This is

#       Darwin, MinGW, and NonStop.
#
#   (3) This script is generated from the Groovy template
#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
#       within the Gradle project.
#
#       You can find Gradle at https://github.com/gradle/gradle/.
#
##############################################################################

import java.io.Serializable;
import java.util.Comparator;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A generalized interval on any ordering, for internal use. Supports {@code null}. Unlike {@link
 * Range}, this allows the use of an arbitrary comparator. This is designed for use in the
 * implementation of subcollections of sorted collection types.
 *

    return set;
  }

  /**
   * Creates a {@code CompactLinkedHashSet} instance, with a high enough "initial capacity" that it
   * <i>should</i> hold {@code expectedSize} elements without rebuilding internal data structures.
   *
   * @param expectedSize the number of elements you expect to add to the returned set
   * @return a new, empty {@code CompactLinkedHashSet} with enough capacity to hold {@code