// 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>

### ✍ 🇨🇻 {🐍

    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);
  }

        ):
            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>

    server.enqueue(MockResponse(body = "hello, OkHttp"))

    val client = OkHttpClient()

    val request =
      Request.Builder()
        .url(server.url("/"))
        .header("Accept", "text/plain")
        .build()
    val response = client.newCall(request).execute()
    assertThat(response.code).isEqualTo(200)
    assertThat(response.body.string()).isEqualTo("hello, OkHttp")

    val recorded = server.takeRequest()

```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"
}

### Crea un file

* Crea un file `main.py` con:

```Python
from fastapi import FastAPI
from typing import Optional

app = FastAPI()


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


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

<details markdown="1">

    serverIpv4.enqueue(
      MockResponse(body = "unexpected call to IPv4"),
    )
    serverIpv6.enqueue(
      MockResponse(body = "hello from IPv6"),
    )

    val call = client.newCall(Request(url))
    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("hello from IPv6")

    // In the process we made one successful connection attempt.

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

    client = TestClient(app)
    return client


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


@needs_py310
def test_q_fixedquery():

	// local to remote
	remoteConn := local.Connection(remoteHost)
	remoteConn.WaitForConnect(context.Background())
	defer testlogger.T.SetErrorTB(t)()

	t.Run("localToRemote", func(t *testing.T) {
		const testPayload = "Hello Grid World!"

		start := time.Now()
		resp, err := remoteConn.Request(context.Background(), handlerTest, []byte(testPayload))
		errFatal(err)
		if string(resp) != testPayload {