from typing import Optional


def say_hi(name: Optional[str] = None):
    if name is not None:
        print(f"Hey {name}!")
    else:

def say_hi(name: str | None):

## 🗄 👩‍💻 🚂

📤 📚 🧰 🏗 👩‍💻 ⚪️➡️ **🗄**.

⚠ 🧰 <a href="https://openapi-generator.tech/" class="external-link" target="_blank">🗄 🚂</a>.

🚥 👆 🏗 **🕸**, 📶 😌 🎛 <a href="https://github.com/hey-api/openapi-ts" class="external-link" target="_blank">🗄-📕-🇦🇪</a>.

## 🏗 📕 🕸 👩‍💻

➡️ ▶️ ⏮️ 🙅 FastAPI 🈸:

//// tab | 🐍 3️⃣.6️⃣ &amp; 🔛

```Python hl_lines="9-11  14-15  18  19  23"

  }

  @Test
  fun encodeMultiplePairs() {
    val body =
      FormBody.Builder()
        .add("sim", "ple")
        .add("hey", "there")
        .add("help", "me")
        .build()
    val expected = "sim=ple&hey=there&help=me"
    assertThat(body.contentLength()).isEqualTo(expected.length.toLong())
    val buffer = Buffer()
    body.writeTo(buffer)

        ImmutableMultimap.<Integer, Object>of(
            0, unhashables.e0(), 2, "hey you", 0, unhashables.e1());
    assertEquals(2, multimap.get(0).size());
    assertTrue(multimap.get(0).contains(unhashables.e0()));
    assertTrue(multimap.get(0).contains(unhashables.e1()));
    assertTrue(multimap.get(2).contains("hey you"));
  }

  public void testEquals() {
    new EqualsTester()

_bug.cgi?id=139848\n  // and https://github.com/twbs/bootstrap/issues/11266\n  -webkit-appearance: listbox;\n}\n\ntextarea {\n  overflow: auto; // Remove the default vertical scrollbar in IE.\n  // Textareas should really only resize vertically so they don't break their (horizontal) containers.\n  resize: vertical;\n}\n\nfieldset {\n  // Browsers set a default `min-width: min-content;` on fieldsets,\n  // unlike e.g. `<div>`s, which have `min-width: 0;` by default.\n  // So we reset that to ensure...

        ImmutableMultimap.<Integer, Object>of(
            0, unhashables.e0(), 2, "hey you", 0, unhashables.e1());
    assertEquals(2, multimap.get(0).size());
    assertTrue(multimap.get(0).contains(unhashables.e0()));
    assertTrue(multimap.get(0).contains(unhashables.e1()));
    assertTrue(multimap.get(2).contains("hey you"));
  }

  public void testEquals() {
    new EqualsTester()

## OpenAPI 客户端生成

有许多工具可以从**OpenAPI**生成客户端。

一个常见的工具是 <a href="https://openapi-generator.tech/" class="external-link" target="_blank">OpenAPI Generator</a>。

如果您正在开发**前端**，一个非常有趣的替代方案是 <a href="https://github.com/hey-api/openapi-ts" class="external-link" target="_blank">openapi-ts</a>。

## 生成一个 TypeScript 前端客户端

让我们从一个简单的 FastAPI 应用开始：

//// tab | Python 3.9+

```Python hl_lines="7-9  12-13  16-17  21"

    assertThat(callbacks.remove()).isEqualTo(Event("1", null, "first event"))
  }

  @Test
  fun retryInvalidFormatIgnored() {
    consumeEvents(
      """
      |retry: 22
      |
      |retry: hey
      |
      """.trimMargin(),
    )
    assertThat(callbacks.remove()).isEqualTo(22L)
  }

  @Test
  fun namePrefixIgnored() {
    consumeEvents(
      """
      |data: a

  }

  @Test
  fun serverReadsHeadersData() {
    assumeNotWindows()
    enableProtocol(Protocol.HTTP_2)
    val body =
      MockStreamHandler()
        .exhaustResponse()
        .receiveRequest("hey\n")
        .receiveRequest("whats going on\n")
        .exhaustRequest()
    server.enqueue(
      MockResponse.Builder()
        .clearHeaders()
        .addHeader("h1", "v1")
        .addHeader("h2", "v2")