private final ForwardingWrapperTester tester = new ForwardingWrapperTester();

  public void testGoodForwarder() {
    tester.testForwarding(
        Arithmetic.class,
        new Function<Arithmetic, Arithmetic>() {
          @Override
          public Arithmetic apply(Arithmetic arithmetic) {
            return new ForwardingArithmetic(arithmetic);
          }
        });
    tester.testForwarding(

Wir importieren das Submodul `items` direkt, anstatt nur seine Variable `router` zu importieren.

Das liegt daran, dass wir im Submodul `users` auch eine weitere Variable namens `router` haben.

Wenn wir eine nach der anderen importiert hätten, etwa:

```Python
from .routers.items import router
from .routers.users import router
```

 * one can get a better result, as only a few registry suffixes are addressable. However, the most
 * useful test to determine if a domain is a plausible web host is {@link #hasPublicSuffix()}. This
 * will return {@code true} for many domains which (currently) are not hosts, such as {@code "com"},
 * but given that any public suffix may become a host without warning, it is better to err on the

@item_router.get("/{item_id}")
def get_item(item_id: str, user_id: Optional[str] = None):
    if user_id is None:
        return {"item_id": item_id}
    else:
        return {"item_id": item_id, "user_id": user_id}


app.include_router(user_router, prefix="/users")
app.include_router(item_router, prefix="/items")

app.include_router(item_router, prefix="/users/{user_id}/items")

  }

  public void testNullEqualityGroup() {
    EqualsTester tester = new EqualsTester();
    try {
      tester.addEqualityGroup((Object[]) null);
      fail();
    } catch (NullPointerException e) {
    }
  }

  public void testNullObjectInEqualityGroup() {
    EqualsTester tester = new EqualsTester();
    try {
      tester.addEqualityGroup(1, null, 3);
      fail();

  private final ForwardingWrapperTester tester = new ForwardingWrapperTester();

  public void testGoodForwarder() {
    tester.testForwarding(
        Arithmetic.class,
        new Function<Arithmetic, Arithmetic>() {
          @Override
          public Arithmetic apply(Arithmetic arithmetic) {
            return new ForwardingArithmetic(arithmetic);
          }
        });
    tester.testForwarding(

### ❎ 📛 💥

👥 🏭 🔁 `items` 🔗, ↩️ 🏭 🚮 🔢 `router`.

👉 ↩️ 👥 ✔️ ➕1️⃣ 🔢 📛 `router` 🔁 `users`.

🚥 👥 ✔️ 🗄 1️⃣ ⏮️ 🎏, 💖:

```Python
from .routers.items import router
from .routers.users import router
```

`router` ⚪️➡️ `users` 🔜 📁 1️⃣ ⚪️➡️ `items` & 👥 🚫🔜 💪 ⚙️ 👫 🎏 🕰.

, 💪 ⚙️ 👯‍♂️ 👫 🎏 📁, 👥 🗄 🔁 🔗:

These **"type hints"** or annotations are a special syntax that allow declaring the <abbr title="for example: str, int, float, bool">type</abbr> of a variable.

By declaring types for your variables, editors and tools can give you better support.

This is just a **quick tutorial / refresher** about Python type hints. It covers only the minimum necessary to use them with **FastAPI**... which is actually very little.

    ok: bool


invoices_callback_router = APIRouter()


@invoices_callback_router.post(
    "{$callback_url}/invoices/{$request.body.id}", response_model=InvoiceEventReceived
)
def invoice_notification(body: InvoiceEvent):
    pass  # pragma: nocover


class Event(BaseModel):
    name: str
    total: float


events_callback_router = APIRouter()

		"age":        user.Age,
		"birthday":   user.Birthday,
		"active":     true,
	}
	checkField(t, userSchema, reflectValue, values)

	var f *bool
	// test setter
	newValues := map[string]interface{}{
		"name":       "valuer_and_setter_2",
		"id":         2,
		"created_at": time.Now(),
		"updated_at": nil,
		"deleted_at": time.Now(),
		"age":        20,
		"birthday":   time.Now(),
		"active":     f,
	}