@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: Optional[str] = None):
    return {"item_id": item_id, "q": q}
```

**Nota**:

e vuoi approfondire, consulta la sezione  _"In a hurry?"_ su <a href="https://fastapi.tiangolo.com/async/#in-a-hurry" target="_blank">`async` e `await` nella documentazione</a>.

</details>

    try {
      helper.add(null, "Hello");
      fail("No exception was thrown.");
    } catch (NullPointerException expected) {
    }
  }

  @GwtIncompatible // Class names are obfuscated in GWT
  public void testToString_addWithNullValue() {
    final String result = MoreObjects.toStringHelper(new TestClass()).add("Hello", null).toString();

    assertEquals("TestClass{Hello=null}", result);
  }

    )
    val response = client.newCall(request().build()).execute()
    val responseBody = response.body
    assertThat(responseBody.string(), "Expected response body to be valid")
      .isEqualTo("Hello, Hello, Hello")
    responseBody.close()
    networkLogs
      .assertLogEqual("--> GET $url http/1.1")
      .assertLogEqual("Host: $host")
      .assertLogEqual("Connection: Keep-Alive")

      Equivalence.equals().onResultOf(LengthFunction.INSTANCE);

  public void testWrap() {
    new EqualsTester()
        .addEqualityGroup(
            LENGTH_EQUIVALENCE.wrap("hello"),
            LENGTH_EQUIVALENCE.wrap("hello"),
            LENGTH_EQUIVALENCE.wrap("world"))
        .addEqualityGroup(LENGTH_EQUIVALENCE.wrap("hi"), LENGTH_EQUIVALENCE.wrap("yo"))
        .addEqualityGroup(

    client.webSocket!!.finishReader()
    server.listener.assertClosed(1000, "Hello!")
    client.listener.assertClosed(1000, "Goodbye!")
  }

  @Test
  fun clientCloseThenMethodsReturnFalse() {
    client.webSocket!!.close(1000, "Hello!")
    assertThat(client.webSocket!!.close(1000, "Hello!")).isFalse()
    assertThat(client.webSocket!!.send("Hello!")).isFalse()
  }

  @Test
  fun clientCloseWith0Fails() {

    try {
      helper.add(null, "Hello");
      fail("No exception was thrown.");
    } catch (NullPointerException expected) {
    }
  }

  @GwtIncompatible // Class names are obfuscated in GWT
  public void testToString_addWithNullValue() {
    final String result = MoreObjects.toStringHelper(new TestClass()).add("Hello", null).toString();

    assertEquals("TestClass{Hello=null}", result);
  }

    // Then you could use it with other programs, like
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "🚪 📋"

    <div class="termy">

    ```console
    // Create an env var MY_NAME
    $ $Env:MY_NAME = "Wade Wilson"

    // Use it with other programs, like
    $ echo "Hello $Env:MY_NAME"

    Hello Wade Wilson
    ```

    </div>

### ✍ 🇨🇻 {🐍

        ):
            if q:
                return f"Hello {q}"
            else:
                return "Hello World"

    client = TestClient(app)
    return client


@needs_py310
def test_query_params_str_validations_no_query():
    client = get_client()
    response = client.get("/items/")
    assert response.status_code == 200
    assert response.json() == "Hello World"


@needs_py310

<p>
For example, in this program:
</p>

<pre>
var a string

func f() {
	print(a)
}

func hello() {
	a = "hello, world"
	go f()
}
</pre>

<p>
calling <code>hello</code> will print <code>"hello, world"</code>
at some point in the future (perhaps after <code>hello</code> has returned).
</p>

<h3 id="goexit">Goroutine destruction</h3>

<p>

```txt
Hello, World from Flask!
```

&amp; 🚥 👆 🚶 <a href="http://localhost:8000/v2" class="external-link" target="_blank">http://localhost:8000/v2</a> 👆 🔜 👀 📨 ⚪️➡️ FastAPI:

```JSON
{
    "message": "Hello World"
}