Digamos que você queira declarar o parâmetro de consulta `q` com `min_length` de `3` e ter um valor padrão de `"fixedquery"`:

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

/// note | Nota

Ter um valor padrão de qualquer tipo, incluindo `None`, torna o parâmetro opcional (não obrigatório).

///

## Parâmetros obrigatórios { #required-parameters }

例如，`dependency_c` 可以依赖于 `dependency_b`，而 `dependency_b` 则依赖于 `dependency_a`。

{* ../../docs_src/dependencies/tutorial008_an_py39.py hl[6,14,22] *}

所有这些依赖都可以使用 `yield`。

在这种情况下，`dependency_c` 在执行其退出代码时需要 `dependency_b`（此处称为 `dep_b`）的值仍然可用。

而 `dependency_b` 反过来则需要 `dependency_a`（此处称为 `dep_a` ）的值在其退出代码中可用。

{* ../../docs_src/dependencies/tutorial008_an_py39.py hl[18:19,26:27] *}

同样，你可以混合使用带有 `yield` 或 `return` 的依赖。

你也可以声明一个依赖于多个带有 `yield` 的依赖，等等。

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

### Exceptions auslösen { #raise-exceptions }

Die Abhängigkeiten können Exceptions `raise`n, genau wie normale Abhängigkeiten:

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

### Rückgabewerte { #return-values }

{* ../../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 }

## Import `File` and `Form` { #import-file-and-form }

{* ../../docs_src/request_forms_and_files/tutorial001_an_py39.py hl[3] *}

## Define `File` and `Form` parameters { #define-file-and-form-parameters }

Create file and form parameters the same way you would for `Body` or `Query`:

{* ../../docs_src/request_forms_and_files/tutorial001_an_py39.py hl[10:12] *}

{* ../../docs_src/request_forms_and_files/tutorial001_an_py39.py hl[3] *}

## `File` und `Form`-Parameter definieren { #define-file-and-form-parameters }

Erstellen Sie Datei- und Formularparameter, so wie Sie es auch mit `Body` oder `Query` machen würden:

{* ../../docs_src/request_forms_and_files/tutorial001_an_py39.py hl[10:12] *}

```

///

## Імпорт `Form`

Імпортуйте `Form` з `fastapi`:

{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[3] *}

## Оголошення параметрів `Form`

Створюйте параметри форми так само як Ви б створювали `Body` або `Query`:

{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[9] *}