{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[8,13] *}

### Вызов исключений { #raise-exceptions }

Зависимости из dependencies могут вызывать исключения с помощью `raise`, как и обычные зависимости:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[10,15] *}

### Возвращаемые значения { #return-values }

They can declare request requirements (like headers) or other sub-dependencies:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[8,13] *}

### Raise exceptions { #raise-exceptions }

These dependencies can `raise` exceptions, the same as normal dependencies:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[10,15] *}

### Return values { #return-values }

And they can return values or not, the values won't be used.

Pueden declarar requisitos de request (como headers) u otras sub-dependencias:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[8,13] *}

### Lanzar excepciones { #raise-exceptions }

Estas dependencias pueden `raise` excepciones, igual que las dependencias normales:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[10,15] *}

### Valores de retorno { #return-values }

Dependências podem declarar requisitos de requisições (como cabeçalhos) ou outras subdependências:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[8,13] *}

### Levantar exceções { #raise-exceptions }

Essas dependências podem `raise` exceções, da mesma forma que dependências comuns:

{* ../../docs_src/dependencies/tutorial006_an_py39.py hl[10,15] *}

### Valores de retorno { #return-values }

이를 위해 `__call__` 메서드를 선언합니다:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[12] *}

이 경우, **FastAPI**는 추가 매개변수와 하위 의존성을 확인하기 위해 `__call__`을 사용하게 되며,
나중에 *경로 연산 함수*에서 매개변수에 값을 전달할 때 이를 호출하게 됩니다.

## 인스턴스 매개변수화하기

이제 `__init__`을 사용하여 의존성을 "매개변수화"할 수 있는 인스턴스의 매개변수를 선언할 수 있습니다:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[9] *}

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[9] *}

In diesem Fall wird **FastAPI** `__init__` nie berühren oder sich darum kümmern, wir werden es direkt in unserem Code verwenden.

## Eine Instanz erstellen { #create-an-instance }

Wir könnten eine Instanz dieser Klasse erstellen mit:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[18] *}

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[9] *}

В этом случае **FastAPI** вовсе не трогает `__init__` и не зависит от него — мы используем его напрямую в нашем коде.

## Создаём экземпляр { #create-an-instance }

Мы можем создать экземпляр этого класса так:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[18] *}

from tests.utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial002_py39"),
        pytest.param("tutorial002_py310", marks=needs_py310),
        pytest.param("tutorial002_an_py39"),
        pytest.param("tutorial002_an_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.custom_request_and_route.{request.param}")

Let's say that you want to declare the `q` query parameter to have a `min_length` of `3`, and to have a default value of `"fixedquery"`:

{* ../../docs_src/query_params_str_validations/tutorial005_an_py39.py hl[9] *}

/// note

Having a default value of any type, including `None`, makes the parameter optional (not required).

///

## Required parameters { #required-parameters }

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[9] *}

Neste caso, o **FastAPI** nunca tocará ou se importará com o `__init__`, nós vamos utilizar diretamente em nosso código.

## Crie uma instância { #create-an-instance }

Nós poderíamos criar uma instância desta classe com:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[18] *}