O Pydantic tem um comportamento especial quando você usa `Optional` ou `Union[Something, None]` sem um valor padrão. Você pode ler mais sobre isso na documentação do Pydantic sobre <a href="https://docs.pydantic.dev/2.3/usage/models/#required-fields" class="external-link" target="_blank">campos Opcionais Obrigatórios</a>.

///


## Type Hints com Metadados de Anotações

        }
    }

    public void test_getDocumentExpires() {
        // Test with null config
        assertNull(crawlingInfoHelper.getDocumentExpires(null));

        // Test with documentExpires field set (fallback behavior)
        final long currentTime = 1704067200000L; // 2024-01-01 00:00:00 UTC
        ComponentUtil.register(new SystemHelper() {
            @Override
            public long getCurrentTimeAsLong() {

///

/// tip | Consejo

pkg debug/dwarf, const ClassStringAlt = 14
pkg debug/dwarf, const ClassStringAlt Class
pkg debug/dwarf, method (*Data) LineReader(*Entry) (*LineReader, error)
pkg debug/dwarf, method (*Entry) AttrField(Attr) *Field
pkg debug/dwarf, method (*LineReader) Next(*LineEntry) error
pkg debug/dwarf, method (*LineReader) Reset()
pkg debug/dwarf, method (*LineReader) Seek(LineReaderPos)

**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`.

	}

	if createdByRel, ok := userSchema.Relationships.Relations["CreatedBy"]; ok {
		if createdByRel.FieldSchema != userSchema {
			t.Fatalf("expects same field schema, but got new %p, old %p", createdByRel.FieldSchema, userSchema)
		}
	} else {
		t.Fatalf("expects created by relations, but not found")
	}
}

func TestEmbeddedHas(t *testing.T) {
	type Toy struct {

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
		}

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

{* ../../docs_src/settings/tutorial001.py hl[2,5:8,11] *}

////

//// tab | Pydantic v1

/// info

		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{

   * near-simultaneously) then this is the first reason known to this peer.
   */
  internal var errorCode: ErrorCode? = null
    get() = withLock { field }

  /** The exception that explains [errorCode]. Null if no exception was provided. */
  internal var errorException: IOException? = null

  init {
    if (headers != null) {