@app.get("/app")
def read_main(request: Request):
    return {"message": "Hello World", "root_path": request.scope.get("root_path")}


client = TestClient(app)


def test_main():
    response = client.get("/app")
    assert response.status_code == 200
    assert response.json() == {"message": "Hello World", "root_path": "/api/v1"}


def test_openapi():
    response = client.get("/openapi.json")

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// tip | "Dica"

O segundo argumento para <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> é o valor padrão a ser retornado.

Se não for fornecido, é `None` por padrão, Aqui fornecemos `"World"` como o valor padrão a ser usado.

///

      <T extends @Nullable Object> Scenario<?> mutate(Scenario<T> scenario) {
        List<Iterable<T>> words = Lists.newArrayList();
        words.add(Collections.<T>emptyList());
        for (T t : scenario.strictlyOrderedList) {
          words.add(asList(t));
          for (T s : scenario.strictlyOrderedList) {
            words.add(asList(t, s));
          }
        }
        return new Scenario<Iterable<T>>(

      <T extends @Nullable Object> Scenario<?> mutate(Scenario<T> scenario) {
        List<Iterable<T>> words = Lists.newArrayList();
        words.add(Collections.<T>emptyList());
        for (T t : scenario.strictlyOrderedList) {
          words.add(asList(t));
          for (T s : scenario.strictlyOrderedList) {
            words.add(asList(t, s));
          }
        }
        return new Scenario<Iterable<T>>(

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

E se você for até <a href="http://localhost:8000/v2" class="external-link" target="_blank">http://localhost:8000/v2</a>, você verá o retorno do FastAPI:

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

Mit `app.include_router()` können wir jeden `APIRouter` zur Hauptanwendung `FastAPI` hinzufügen.

Es wird alle Routen von diesem Router als Teil von dieser inkludieren.

/// note | "Technische Details"

Tatsächlich wird intern eine *Pfadoperation* für jede *Pfadoperation* erstellt, die im `APIRouter` deklariert wurde.

Hinter den Kulissen wird es also tatsächlich so funktionieren, als ob alles dieselbe einzige Anwendung wäre.

///

  }

  @Override public void onOpen(WebSocket webSocket, Response response) {
    webSocket.send("Hello...");
    webSocket.send("...World!");
    webSocket.send(ByteString.decodeHex("deadbeef"));
    webSocket.close(1000, "Goodbye, World!");
  }

  @Override public void onMessage(WebSocket webSocket, String text) {
    System.out.println("MESSAGE: " + text);
  }

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

Eğer <a href="http://localhost:8000/v2/" class="external-link" target="_blank">http://localhost:8000/v2/</a> adresine giderseniz, FastAPI'dan gelen yanıtı göreceksiniz:

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

{!> ../../docs_src/python_types/tutorial006.py!}
```

////

/// info

De interne types tussen vierkante haakjes worden “typeparameters” genoemd.

In dit geval is `str` de typeparameter die wordt doorgegeven aan `List` (of `list` in Python 3.9 en hoger).

///

Dat betekent: “de variabele `items` is een `list`, en elk van de items in deze list is een `str`”.

/// tip

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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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