### Création d'un `Enum`

Importez `Enum` et créez une sous-classe qui hérite de `str` et `Enum`.

En héritant de `str` la documentation sera capable de savoir que les valeurs doivent être de type `string` et pourra donc afficher cette `Enum` correctement.

Créez ensuite des attributs de classe avec des valeurs fixes, qui seront les valeurs autorisées pour cette énumération.

```Python hl_lines="1  6-9"

    "size": "XL"
  }
}
```

#### O `HTTPException` do FastAPI vs o `HTTPException` do Starlette.

O **FastAPI** tem o seu próprio `HTTPException`.

E a classe de erro `HTTPException` do **FastAPI** herda da classe de erro do `HTTPException` do Starlette.

A diferença entre os dois é a de que o `HTTPException` do **FastAPI** permite que você adicione *headers* que serão incluídos nas *responses*.

const (
	// ResourceHeader.Class and Question.Class
	ClassINET   Class = 1
	ClassCSNET  Class = 2
	ClassCHAOS  Class = 3
	ClassHESIOD Class = 4

	// Question.Class
	ClassANY Class = 255
)

var classNames = map[Class]string{
	ClassINET:   "ClassINET",
	ClassCSNET:  "ClassCSNET",
	ClassCHAOS:  "ClassCHAOS",
	ClassHESIOD: "ClassHESIOD",
	ClassANY:    "ClassANY",
}

// String implements fmt.Stringer.String.

		r.Hdr = dns.RR_Header{Name: host, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: defaultTTLInSeconds}
		r.AAAA = ip.AsSlice()
		answers[i] = r
	}
	return answers
}

func cname(host string, targetHost string) []dns.RR {
	answer := new(dns.CNAME)
	answer.Hdr = dns.RR_Header{
		Name:   host,
		Rrtype: dns.TypeCNAME,
		Class:  dns.ClassINET,
		Ttl:    defaultTTLInSeconds,
	}
	answer.Target = targetHost

//sys	RegQueryInfoKey(key Handle, class *uint16, classLen *uint32, reserved *uint32, subkeysLen *uint32, maxSubkeyLen *uint32, maxClassLen *uint32, valuesLen *uint32, maxValueNameLen *uint32, maxValueLen *uint32, saLen *uint32, lastWriteTime *Filetime) (regerrno error) = advapi32.RegQueryInfoKeyW

	r0, _, _ := Syscall9(procRegEnumKeyExW.Addr(), 8, uintptr(key), uintptr(index), uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(nameLen)), uintptr(unsafe.Pointer(reserved)), uintptr(unsafe.Pointer(class)), uintptr(unsafe.Pointer(classLen)), uintptr(unsafe.Pointer(lastWriteTime)), 0)
	if r0 != 0 {
		regerrno = Errno(r0)

Primeiro, você precisa importar `BaseModel` do `pydantic`:

```Python hl_lines="4"
{!../../../docs_src/body/tutorial001.py!}
```

## Crie seu modelo de dados

Então você declara seu modelo de dados como uma classe que herda `BaseModel`.

Utilize os tipos Python padrão para todos os atributos:

```Python hl_lines="7-11"
{!../../../docs_src/body/tutorial001.py!}
```

import org.codehaus.groovy.ast.stmt.ThrowStatement;
import org.codehaus.groovy.ast.stmt.TryCatchStatement;
import org.codehaus.groovy.ast.stmt.WhileStatement;
import org.codehaus.groovy.classgen.BytecodeExpression;

import java.util.List;
import java.util.ListIterator;

/**
 * Groovy AST visitor that allows to replace both statements and expressions.
 */

func (r *Resolver) exchange(ctx context.Context, server string, q dnsmessage.Question, timeout time.Duration, useTCP, ad bool) (dnsmessage.Parser, dnsmessage.Header, error) {
	q.Class = dnsmessage.ClassINET
	id, udpReq, tcpReq, err := newRequest(q, ad)
	if err != nil {
		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotMarshalDNSMessage
	}
	var networks []string
	if useTCP {
		networks = []string{"tcp"}

	}
	return nil, 0
}

func cgoLookupCNAME(ctx context.Context, name string) (cname string, err error, completed bool) {
	resources, err := resSearch(ctx, name, int(dnsmessage.TypeCNAME), int(dnsmessage.ClassINET))
	if err != nil {
		return
	}
	cname, err = parseCNAMEFromResources(resources)
	if err != nil {
		return "", err, false
	}
	return cname, nil, true
}