import java.lang.annotation.Target;

/**
 * Marks a method as an event subscriber.
 *
 * <p>The type of event will be indicated by the method's first (and only) parameter, which cannot
 * be primitive. If this annotation is applied to methods with zero parameters, or more than one
 * parameter, the object containing the method will not be able to register for event delivery from
 * the {@link EventBus}.
 *

   *       to construct the sample instances. In case of tie, the candidate constructors or
   *       factories are tried one after another until one can be used to construct sample
   *       instances.
   *   <li>For the constructor or static factory method used to construct instances, it's checked

////

In diesem Fall ist dieses `__call__` das, was **FastAPI** verwendet, um nach zusätzlichen Parametern und Unterabhängigkeiten zu suchen, und das ist es auch, was später aufgerufen wird, um einen Wert an den Parameter in Ihrer *Pfadoperation-Funktion* zu übergeben.

## Die Instanz parametrisieren

Und jetzt können wir `__init__` verwenden, um die Parameter der Instanz zu deklarieren, die wir zum `Parametrisieren` der Abhängigkeit verwenden können:

# Body - Fields

The same way you can declare additional validation and metadata in *path operation function* parameters with `Query`, `Path` and `Body`, you can declare validation and metadata inside of Pydantic models using Pydantic's `Field`.

## Import `Field`

First, you have to import it:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}


/// warning

    /**
     * Moves the cursor up. If the parameter y is negative it moves the cursor down.
     *
     * @param y the number of lines to move up
     * @return this Ansi instance
     */
    public Ansi cursorUp(final int y) {
        return y > 0 ? appendEscapeSequence('A', y) : y < 0 ? cursorDown(-y) : this;
    }

    /**
     * Moves the cursor down. If the parameter y is negative it moves the cursor up.
     *

/// tip

Some editors check for unused function parameters, and show them as errors.

Using these `dependencies` in the *path operation decorator* you can make sure they are executed while avoiding editor/tooling errors.

It might also help avoid confusion for new developers that see an unused parameter in your code and could think it's unnecessary.

///

/// info

{!> ../../docs_src/body_nested_models/tutorial002.py!}
```

### Declare a `list` with a type parameter

To declare types that have type parameters (internal types), like `list`, `dict`, `tuple`:

* If you are in a Python version lower than 3.9, import their equivalent version from the `typing` module
* Pass the internal type(s) as "type parameters" using square brackets: `[` and `]`

In Python 3.9 it would be:

```Python

Dieser Teil ist ziemlich normal, der größte Teil des Codes ist Ihnen wahrscheinlich bereits bekannt:

```Python hl_lines="9-13  36-53"
{!../../docs_src/openapi_callbacks/tutorial001.py!}
```

/// tip | "Tipp"

### Request `POST` to plugin endpoint

Query parameters:

| Parameter Name | Value Type | Purpose                                                                 |
|----------------|------------|-------------------------------------------------------------------------|

    summary: Optional[str] = None
    description: Optional[str] = None
    externalDocs: Optional[ExternalDocumentation] = None
    operationId: Optional[str] = None
    parameters: Optional[List[Union[Parameter, Reference]]] = None
    requestBody: Optional[Union[RequestBody, Reference]] = None
    # Using Any for Specification Extensions
    responses: Optional[Dict[str, Union[Response, Any]]] = None