### 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">

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[8:9] *}

Eso es todo.

**2 líneas**.

Y tiene la misma forma y estructura que todas tus *path operation functions*.

Puedes pensar en ella como una *path operation function* sin el "decorador" (sin el `@app.get("/some-path")`).

Y puede devolver lo que quieras.

En este caso, esta dependencia espera:

* Un parámetro de query opcional `q` que es un `str`.

		*es = EncryptedString(bytes.TrimPrefix(value, []byte("hello")))
	case string:
		*es = EncryptedString(strings.TrimPrefix(value, "hello"))
	default:
		return fmt.Errorf("unsupported data %#v", dbValue)
	}
	return nil
}

func (es EncryptedString) Value(ctx context.Context, field *schema.Field, dst reflect.Value, fieldValue interface{}) (interface{}, error) {
	return "hello" + string(es), nil
}

type CustomSerializer struct {

$ echo "Hello $MY_NAME"

Hello Wade Wilson
```

</div>

////

//// tab | Windows PowerShell

<div class="termy">

```console
// Erstelle eine Umgebungsvariable MY_NAME
$ $Env:MY_NAME = "Wade Wilson"

// Verwende sie mit anderen Programmen, etwa
$ echo "Hello $Env:MY_NAME"

Hello Wade Wilson
```

</div>

////

    assertHash(1, 0xa78ddff5adae8d10L, 0x128900ef20900135L, "hello");
    assertHash(2, 0x8a486b23f422e826L, 0xf962a2c58947765fL, "hello ");
    assertHash(3, 0x2ea59f466f6bed8cL, 0xc610990acc428a17L, "hello w");
    assertHash(4, 0x79f6305a386c572cL, 0x46305aed3483b94eL, "hello wo");
    assertHash(5, 0xc2219d213ec1f1b5L, 0xa1d8e2e0a52785bdL, "hello wor");
    assertHash(

    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() {

        }
    }

    public void test_startProcess_basicCommand() {
        String sessionId = "test_session";
        List<String> cmdList = Arrays.asList("echo", "hello");
        Consumer<ProcessBuilder> pbCall = pb -> {
            pb.redirectErrorStream(true);
        };

        try {
            JobProcess jobProcess = processHelper.startProcess(sessionId, cmdList, pbCall);

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

Hello Wade Wilson
```

</div>

////

//// tab | Windows PowerShell

<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>

////

## 파이썬에서 환경 변수 읽기

        StringSource source = new StringSource("Hello World!");

        try (InputStream is = source.getInputStream();
                Scanner scanner = new Scanner(is)) {
            assertEquals("Hello World!", scanner.nextLine());
        }
    }

    @Test
    void testGetLocation() {
        StringSource source = new StringSource("Hello World!");
        assertEquals("(memory)", source.getLocation());

    }

    public void test_lambda_expression() {
        BooleanFunction<String> startsWithHello = s -> s != null && s.startsWith("hello");

        assertTrue(startsWithHello.apply("hello world"));
        assertTrue(startsWithHello.apply("hello"));
        assertFalse(startsWithHello.apply("hi world"));
        assertFalse(startsWithHello.apply(""));
        assertFalse(startsWithHello.apply(null));
    }