**Spoiler alert**: il tutorial - Guida Utente include:

* Dichiarazione di **parameters** da altri posti diversi come: **headers**, **cookies**, **form fields** e **files**.
* Come stabilire **vincoli di validazione** come `maximum_length` o `regex`.

### 创建 `Settings` 对象

从 Pydantic 导入 `BaseSettings` 并创建一个子类，与 Pydantic 模型非常相似。

与 Pydantic 模型一样，您使用类型注释声明类属性，还可以指定默认值。

您可以使用与 Pydantic 模型相同的验证功能和工具，比如不同的数据类型和使用 `Field()` 进行附加验证。

```Python hl_lines="2  5-8  11"
{!../../docs_src/settings/tutorial001.py!}
```

/// tip

如果您需要一个快速的复制粘贴示例，请不要使用此示例，而应使用下面的最后一个示例。

///

Você pode utilizar todas as ferramentas e funcionalidades de validação que são utilizadas nos modelos do Pydantic, como tipos de dados diferentes e validações adicionei com `Field()`.

//// tab | Pydantic v2

```Python hl_lines="2  5-8  11"
{!> ../../docs_src/settings/tutorial001.py!}
```

////

//// tab | Pydantic v1

/// info

      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You

      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You

      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You

      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You

func TestFields(t *testing.T) {
	for _, tt := range fieldstests {
		b := []byte(tt.s)
		a := Fields(b)

		// Appending to the results should not change future results.
		var x []byte
		for _, v := range a {
			x = append(v, 'z')
		}

		result := sliceOfString(a)
		if !slices.Equal(result, tt.a) {
			t.Errorf("Fields(%q) = %v; want %v", tt.s, a, tt.a)
			continue
		}

	errCmpInvalidBoolOperator = errors.New("invalid comparison operator for boolean arguments")
)

// Value represents a value of restricted type reduced from an
// expression represented by an ASTNode. Only one of the fields is
// non-nil.
//
// In cases where we are fetching data from a data source (like csv),
// the type may not be determined yet. In these cases, a byte-slice is
// used.
type Value struct {
	value interface{}
}

		if obj.As(i) >= obj.A_ARCHSPECIFIC {
			instructions[s] = obj.As(i) + obj.ABaseARM
		}
	}
	// Annoying aliases.
	instructions["B"] = obj.AJMP
	instructions["BL"] = obj.ACALL
	// MCR differs from MRC by the way fields of the word are encoded.
	// (Details in arm.go). Here we add the instruction so parse will find
	// it, but give it an opcode number known only to us.
	instructions["MCR"] = aMCR

	return &Arch{