[AccessHeadersJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/AccessHeaders.java
 [AccessHeadersKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/AccessHeaders.kt

 * [PersistentCookieJar](https://github.com/franmontiel/PersistentCookieJar): A persistent `CookieJar`.
 * ⬜️ [Picasso](https://github.com/square/picasso): A powerful image downloading and caching library for Android.
 * ⬜️ [Retrofit](https://github.com/square/retrofit): Type-safe HTTP client for Android and Java by Square.
 * [ScribeJava](https://github.com/scribejava/scribejava): Simple OAuth library for Java

    url.set("https://square.github.io/okhttp/")
    licenses {
      license {
        name.set("The Apache Software License, Version 2.0")
        url.set("https://www.apache.org/licenses/LICENSE-2.0.txt")
        distribution.set("repo")
      }
    }
    scm {
      connection.set("scm:git:https://github.com/square/okhttp.git")

    y: float


@app.post("/model-with-tuple/")
def post_model_with_tuple(item_group: ItemGroup):
    return item_group


@app.post("/tuple-of-models/")
def post_tuple_of_models(square: tuple[Coordinate, Coordinate]):
    return square


@app.post("/tuple-form/")
def hello(values: tuple[int, int] = Form()):
    return values


client = TestClient(app)


def test_model_with_tuple_valid():

 [okhttp_312x]: https://github.com/square/okhttp/tree/okhttp_3.12.x
 [okio]: https://github.com/square/okio
 [post_example]: https://raw.github.com/square/okhttp/master/samples/guide/src/main/java/okhttp3/guide/PostExample.java
 [r8_proguard]: https://square.github.io/okhttp/features/r8_proguard/
 [recipes]: https://square.github.io/okhttp/recipes/
 [snap]: https://s01.oss.sonatype.org/content/repositories/snapshots/

import org.junit.jupiter.api.Test
import org.junit.jupiter.api.extension.RegisterExtension

@Flaky
@Tag("Slow")
class WebSocketHttpTest {
  // Flaky https://github.com/square/okhttp/issues/4515
  // Flaky https://github.com/square/okhttp/issues/4953
  @RegisterExtension
  var clientTestRule = configureClientTestRule()

  @RegisterExtension
  var platform = PlatformRule()

  @RegisterExtension

      }
    ```

 [CustomTrustJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CustomTrust.java
 [CustomTrustKotlin]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/kt/CustomTrust.kt
 [CertificatePinningJava]: https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/CertificatePinning.java

/*
 * Copyright (C) 2016 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright (C) 2025 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

```

### Generic types { #generic-types }

Some types can take "type parameters" in square brackets, to define their internal types, for example a "list of strings" would be declared `list[str]`.

These types that can take type parameters are called **Generic types** or **Generics**.

You can use the same builtin types as generics (with square brackets and types inside):

* `list`
* `tuple`
* `set`
* `dict`