{* ../../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 }

# Byte-compiled / optimized / DLL files
__pycache__/
*.py[cod]
*$py.class

# C extensions
*.so

# Distribution / packaging
.Python
build/
develop-eggs/
dist/
downloads/
eggs/
.eggs/
lib/
lib64/
parts/
sdist/
var/
wheels/
*.egg-info/
.installed.cfg
*.egg
MANIFEST

# PyInstaller
#  Usually these files are written by a python script from a template

<div class="termy">

```console
// Here we don't set the env var yet
$ python main.py

// As we didn't set the env var, we get the default value

Hello World from Python

// But if we create an environment variable first
$ export MY_NAME="Wade Wilson"

// And then call the program again
$ python main.py

// Now it can read the environment variable

Hello Wade Wilson from Python
```

</div>

//// tab | Pydantic v2

{* ../../docs_src/path_operation_advanced_configuration/tutorial007_py39.py hl[15:20, 22] *}

////

//// tab | Pydantic v1

{* ../../docs_src/path_operation_advanced_configuration/tutorial007_pv1_py39.py hl[15:20, 22] *}

////

/// info | Información

//// tab | Pydantic v2

{* ../../docs_src/path_operation_advanced_configuration/tutorial007_py39.py hl[15:20, 22] *}

////

//// tab | Pydantic v1

{* ../../docs_src/path_operation_advanced_configuration/tutorial007_pv1_py39.py hl[15:20, 22] *}

////

/// info | Informação

Deklarieren Sie die erforderlichen **Header-Parameter** in einem **Pydantic-Modell** und dann den Parameter als `Header`:

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

Declare the **header parameters** that you need in a **Pydantic model**, and then declare the parameter as `Header`:

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

{* ../../docs_src/path_params/tutorial005.py hl[16] *}

### 문서 확인

*경로 매개변수*에 사용할 수 있는 값은 미리 정의되어 있으므로 대화형 문서에서 잘 표시됩니다:

<img src="/img/tutorial/path-params/image03.png">

### 파이썬 *열거형*으로 작업하기

*경로 매개변수*의 값은 *열거형 멤버*가 됩니다.

#### *열거형 멤버* 비교

열거형 `ModelName`의 *열거형 멤버*를 비교할 수 있습니다:

{* ../../docs_src/path_params/tutorial005.py hl[17] *}

#### *열거형 값* 가져오기

{* ../../docs_src/path_params_numeric_validations/tutorial002_py39.py hl[7] *}

Но имейте в виду, что если вы используете `Annotated`, вы не столкнётесь с этой проблемой, так как вы не используете значения по умолчанию параметров функции для `Query()` или `Path()`.

{* ../../docs_src/path_params_numeric_validations/tutorial002_an_py39.py *}

        "//third_party/pathways/...",
        "//third_party/py/cloud_ml_autoflow/...",
        "//third_party/py/envlogger/...",
        "//third_party/py/gldm/...",
        "//third_party/py/guesslang/...",
        "//third_party/py/keras/...",
        "//third_party/py/tf_keras/...",
        "//third_party/yggdrasil_decision_forests/...",
        "//waymo/accelerator/...",