{* ../../docs_src/dataclasses_/tutorial001_py310.py hl[1,6:11,18:19] *}

This is still supported thanks to **Pydantic**, as it has [internal support for `dataclasses`](https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel).

So, even with the code above that doesn't use Pydantic explicitly, FastAPI is using Pydantic to convert those standard dataclasses to Pydantic's own flavor of dataclasses.

This page is intended as a summary of MinIO Erasure Coding. For a more complete explanation, see <https://docs.min.io/community/minio-object-store/operations/concepts/erasure-coding.html>.

## Overview

MinIO supports two storage classes, Reduced Redundancy class and Standard class. These classes can be defined using environment variables

I will show you some of the main concepts you should probably keep in mind when deploying a **FastAPI** application (although most of it applies to any other type of web application).

そして、`config.py` を次のように更新します:

{* ../../docs_src/settings/app03_an_py310/config.py hl[9] *}

/// tip | 豆知識

`model_config` 属性は Pydantic の設定専用です。詳しくは [Pydantic: Concepts: Configuration](https://docs.pydantic.dev/latest/concepts/config/) を参照してください。

///

ここでは、Pydantic の `Settings` クラス内で設定 `env_file` を定義し、使用したい dotenv ファイルのファイル名を指定しています。

## Pydantic `Settings` { #pydantic-settings }

다행히 Pydantic은 환경 변수에서 오는 이러한 설정을 처리할 수 있는 훌륭한 유틸리티를 [Pydantic: Settings 관리](https://docs.pydantic.dev/latest/concepts/pydantic_settings/)로 제공합니다.

### `pydantic-settings` 설치하기 { #install-pydantic-settings }

먼저 [가상 환경](../virtual-environments.md)을 만들고 활성화한 다음, `pydantic-settings` 패키지를 설치하세요:

<div class="termy">

```console

	)

	ErrInvalidNumberOfErasureEndpoints = newErrFn(
		"Invalid total number of endpoints for erasure mode",
		"Please provide number of endpoints greater or equal to 2",
		"For more information, please refer to https://docs.min.io/community/minio-object-store/operations/concepts/erasure-coding.html",
	)

	ErrStorageClassValue = newErrFn(

## Explore Further

- [MinIO Erasure Code QuickStart Guide](https://docs.min.io/community/minio-object-store/operations/concepts/erasure-coding.html)
- [Kubernetes Documentation](https://kubernetes.io/docs/home/)

provides protection against multiple node/drive failures and [bit rot](https://github.com/minio/minio/blob/master/docs/erasure/README.md#what-is-bit-rot-protection) using [erasure code](https://docs.min.io/community/minio-object-store/operations/concepts/erasure-coding.html). As the minimum drives required for distributed MinIO is 2 (same as minimum drives required for erasure coding), erasure code automatically kicks in as you launch distributed MinIO.

If one or more drives are offline...

 * <strong>NOTE:</strong> This class is not part of any public api and can be changed or deleted without prior notice.
 *
 * @since 3.0
 */
// TODO Kristian wonders if this class really is necessary and if it overlaps other concepts.
public final class ProjectIndex {

    private final Map<String, MavenProject> projects;

    private final Map<String, Integer> indices;

    public ProjectIndex(List<MavenProject> projects) {

这意味着，在 Python 中从环境变量读取的任何值都是 `str` 类型，任何到不同类型的转换或任何验证都必须在代码中完成。

## Pydantic 的 `Settings` { #pydantic-settings }

幸运的是，Pydantic 提供了一个很好的工具来处理来自环境变量的这些设置：[Pydantic：Settings 管理](https://docs.pydantic.dev/latest/concepts/pydantic_settings/)。

### 安装 `pydantic-settings` { #install-pydantic-settings }

首先，确保你创建并激活了[虚拟环境](../virtual-environments.md)，然后安装 `pydantic-settings` 包：

<div class="termy">

```console