{!> ../../docs_src/security/tutorial004_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="7  48  55-56  59-60  69-75"
{!> ../../docs_src/security/tutorial004_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="7  49  56-57  60-61  70-76"
{!> ../../docs_src/security/tutorial004_an.py!}
```

////

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009.py!}
```

////

//// tab | Python 3.8+ alternative

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009b.py!}
```

////

#### Gebruik van `Union` of `Optional`

//// tab | Pydantic v2

```Python hl_lines="17-22  24"
{!> ../../docs_src/path_operation_advanced_configuration/tutorial007.py!}
```

////

//// tab | Pydantic v1

```Python hl_lines="17-22  24"
{!> ../../docs_src/path_operation_advanced_configuration/tutorial007_pv1.py!}
```

////

/// info

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

In this case, the function parameter `q` will be optional, and will be `None` by default.

/// check

```Python hl_lines="9"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="11"
{!> ../../docs_src/dependencies/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="12"
{!> ../../docs_src/dependencies/tutorial001_an.py!}
```

////

//// tab | Python 3.10+ non-Annotated

/// tip | "Dica"

```Python hl_lines="9"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="11"
{!> ../../docs_src/dependencies/tutorial001_an_py39.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="12"
{!> ../../docs_src/dependencies/tutorial001_an.py!}
```

////

//// tab | Python 3.10+ non-Annotated

/// tip

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

In diesem Fall wird der Funktionsparameter `q` optional, und standardmäßig `None` sein.

/// check

```Python hl_lines="1"
{!../../docs_src/python_types/tutorial003.py!}
```

Поскольку редактор знает типы переменных, вы получаете не только дополнение, но и проверки ошибок:

<img src="/img/python-types/image04.png">

Теперь вы знаете, что вам нужно исправить, преобразовав `age` в строку с `str(age)`:

```Python hl_lines="2"
{!../../docs_src/python_types/tutorial004.py!}
```

## Объявление типов

이를 위해 먼저 `fastapi`에서 `Query`를 임포트합니다:

```Python hl_lines="3"
{!../../docs_src/query_params_str_validations/tutorial002.py!}
```

## 기본값으로 `Query` 사용

이제 `Query`를 매개변수의 기본값으로 사용하여 `max_length` 매개변수를 50으로 설정합니다:

```Python hl_lines="9"
{!../../docs_src/query_params_str_validations/tutorial002.py!}
```

기본값 `None`을 `Query(None)`으로 바꿔야 하므로, `Query`의 첫 번째 매개변수는 기본값을 정의하는 것과 같은 목적으로 사용됩니다.

그러므로:

```Python

# Primeros pasos

Un archivo muy simple de FastAPI podría verse así:

```Python
{!../../docs_src/first_steps/tutorial001.py!}
```

Copia eso a un archivo `main.py`.

Corre el servidor en vivo:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)