# Classes as Dependencies { #classes-as-dependencies }

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example { #a-dict-from-the-previous-example }

In the previous example, we were returning a `dict` from our dependency ("dependable"):

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

# Classes como Dependências { #classes-as-dependencies }

Antes de nos aprofundarmos no sistema de **Injeção de Dependência**, vamos melhorar o exemplo anterior.

## `dict` do exemplo anterior { #a-dict-from-the-previous-example }

No exemplo anterior, nós retornávamos um `dict` da nossa dependência ("injetável"):

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

# Klassen als Abhängigkeiten { #classes-as-dependencies }

Bevor wir tiefer in das **Dependency Injection** System eintauchen, lassen Sie uns das vorherige Beispiel verbessern.

## Ein `dict` aus dem vorherigen Beispiel { #a-dict-from-the-previous-example }

# Классы как зависимости { #classes-as-dependencies }

Прежде чем углубиться в систему **Внедрения Зависимостей**, давайте обновим предыдущий пример.

## `dict` из предыдущего примера { #a-dict-from-the-previous-example }

В предыдущем примере мы возвращали `dict` из нашей зависимости:

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

Но затем мы получаем `dict` в параметре `commons` *функции-обработчика пути*.

# Clases como dependencias { #classes-as-dependencies }

Antes de profundizar en el sistema de **Inyección de Dependencias**, vamos a mejorar el ejemplo anterior.

## Un `dict` del ejemplo anterior { #a-dict-from-the-previous-example }

En el ejemplo anterior, estábamos devolviendo un `dict` de nuestra dependencia ("dependable"):

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

        def serialize_a_uuid(self, v):
            return str(v)

    @app.get("/get_custom_class")
    def return_some_user():
        # Test that the fix also works for custom pydantic classes
        return SomeCustomClass(a_uuid=MyUuid("b8799909-f914-42de-91bc-95c819218d01"))

    client = TestClient(app)

    with client:
        response_simple = client.get("/fast_uuid")

In the previous example, because the classes were different, we had to use the `response_model` parameter. But that also means that we don't get the support from the editor and tools checking the function return type.

But in most of the cases where we need to do something like this, we want the model just to **filter/remove** some of the data as in this example.

///

## Use cases { #use-cases }

Some use cases include:

* Converting non-JSON request bodies to JSON (e.g. <a href="https://msgpack.org/index.html" class="external-link" target="_blank">`msgpack`</a>).
* Decompressing gzip-compressed request bodies.
* Automatically logging all request bodies.

## Handling custom request body encodings { #handling-custom-request-body-encodings }

    }

    if (uncaughtThrowable != null) {
      throw new AssertionError("Uncaught throwable in " + getName(), uncaughtThrowable);
    }
  }

  /**
   * Causes this thread to call the named void method, and asserts that the call returns normally.
   */
  public void callAndAssertReturns(String methodName, Object... arguments) throws Exception {
    checkNotNull(methodName);

    }

    if (uncaughtThrowable != null) {
      throw new AssertionError("Uncaught throwable in " + getName(), uncaughtThrowable);
    }
  }

  /**
   * Causes this thread to call the named void method, and asserts that the call returns normally.
   */
  public void callAndAssertReturns(String methodName, Object... arguments) throws Exception {
    checkNotNull(methodName);