### Defina um sub-modelo

Por exemplo, nós podemos definir um modelo `Image`:

```Python hl_lines="9-11"
{!../../../docs_src/body_nested_models/tutorial004.py!}
```

### Use o sub-modelo como um tipo

E então podemos usa-lo como o tipo de um atributo:

```Python hl_lines="20"
{!../../../docs_src/body_nested_models/tutorial004.py!}
```

Isso significa que o **FastAPI** vai esperar um corpo similar à:

```JSON
{

    assertThat(body.boundary).isEqualTo("123")
    assertThat(body.type).isEqualTo(MultipartBody.MIXED)
    assertThat(body.contentType().toString())
      .isEqualTo("multipart/mixed; boundary=123")
    assertThat(body.parts.size).isEqualTo(1)
    assertThat(body.contentLength()).isEqualTo(33L)
    val buffer = Buffer()
    body.writeTo(buffer)
    assertThat(body.contentLength()).isEqualTo(buffer.size)

    assertThat(body.contentLength()).isEqualTo(3)
    assertThat(bodyToHex(body)).isEqualTo("616263")
    assertThat(bodyToHex(body), "Retransmit body").isEqualTo("616263")
  }

  @Test
  fun byteArrayRange() {
    val contentType = "text/plain".toMediaType()
    val body: RequestBody = ".abcd".toByteArray().toRequestBody(contentType, 1, 3)
    assertThat(body.contentType()).isEqualTo(contentType)

    mockWebServer: MockWebServer,
  ) {
    setUp(protocol, mockWebServer)
    val body = repeat('y', 2048)
    server.enqueue(
      MockResponse.Builder()
        .body(body)
        .throttleBody(1024, 1, TimeUnit.SECONDS)
        .build(),
    ) // Slow connection 1KiB/second.
    server.enqueue(
      MockResponse(body = body),
    )
    client =
      client.newBuilder()

    assertThat(body.name(1)).isEqualTo("space, the")
    assertThat(body.name(2)).isEqualTo("%25")
    assertThat(body.encodedValue(0)).isEqualTo("c%2B%3D%26+d")
    assertThat(body.encodedValue(1)).isEqualTo("final+frontier")
    assertThat(body.encodedValue(2)).isEqualTo("%2525")
    assertThat(body.value(0)).isEqualTo("c+=& d")
    assertThat(body.value(1)).isEqualTo("final frontier")
    assertThat(body.value(2)).isEqualTo("%25")

 * closes its response body. If you invoke [Call.execute] or implement [Callback.onResponse] you
 * must close this body by calling any of the following methods:
 *
 * * `Response.close()`
 * * `Response.body().close()`
 * * `Response.body().source().close()`
 * * `Response.body().charStream().close()`
 * * `Response.body().byteStream().close()`
 * * `Response.body().bytes()`
 * * `Response.body().string()`
 *

    open fun head(): Builder = commonHead()

    open fun post(body: RequestBody): Builder = commonPost(body)

    @JvmOverloads
    open fun delete(body: RequestBody? = commonEmptyRequestBody): Builder = commonDelete(body)

    open fun put(body: RequestBody): Builder = commonPut(body)

    open fun patch(body: RequestBody): Builder = commonPatch(body)

    open fun method(
      method: String,

            - media_type
            - body
            - background
            - raw_headers
            - render
            - init_headers
            - headers
            - set_cookie
            - delete_cookie

::: fastapi.responses.ORJSONResponse
    options:
        members:
            - charset
            - status_code
            - media_type
            - body
            - background

        localhostIpv4,
        localhostIpv6,
      )
    serverIpv4.enqueue(
      MockResponse(body = "unexpected call to IPv4"),
    )
    serverIpv6.enqueue(
      MockResponse(body = "hello from IPv6"),
    )

    val call = client.newCall(Request(url))
    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("hello from IPv6")

    // In the process we made one successful connection attempt.

          if (requestBody.isDuplex()) {
            // Prepare a duplex body so that the application can send a request body later.
            exchange.flushRequest()
            val bufferedRequestBody = exchange.createRequestBody(request, true).buffer()
            requestBody.writeTo(bufferedRequestBody)
          } else {
            // Write the request body if the "Expect: 100-continue" expectation was met.