Pero cuando importas `Query`, `Path`, `Depends`, `Security` y otros de `fastapi`, en realidad son funciones que devuelven clases especiales.

///

## Usar `SecurityScopes`

Ahora actualiza la dependencia `get_current_user`.

Esta es la que usan las dependencias anteriores.

Mas quando você importa `Query`, `Path`, `Depends`, `Security` entre outros de `fastapi`, eles são na verdade funções que retornam classes especiais.

///

## Utilize `SecurityScopes`

Agora atualize a dependência `get_current_user`.

Este é o usado pelas dependências acima.

* `read(size)`: Reads `size` (`int`) bytes/characters of the file.
* `seek(offset)`: Goes to the byte position `offset` (`int`) in the file.
    * E.g., `await myfile.seek(0)` would go to the start of the file.
    * This is especially useful if you run `await myfile.read()` once and then need to read the contents again.
* `close()`: Closes the file.

As all these methods are `async` methods, you need to "await" them.

They tend to require more complex configurations, a message/job queue manager, like RabbitMQ or Redis, but they allow you to run background tasks in multiple processes, and especially, in multiple servers.

But if you need to access variables and objects from the same **FastAPI** app, or you need to perform small background tasks (like sending an email notification), you can simply just use `BackgroundTasks`.

# Extra Models { #extra-models }

Continuing with the previous example, it will be common to have more than one related model.

This is especially the case for user models, because:

* The **input model** needs to be able to have a password.
* The **output model** should not have a password.
* The **database model** would probably need to have a hashed password.

/// danger

This will be especially useful when you use it in a **large code base** where you use **the same dependencies** over and over again in **many *path operations***.

## To `async` or not to `async` { #to-async-or-not-to-async }

{* ../../docs_src/response_model/tutorial006_py310.py hl[29,35] *}

## Recap { #recap }

Use the *path operation decorator's* parameter `response_model` to define response models and especially to ensure private data is filtered out.

In some occasions it might be useful to provide the settings from a dependency, instead of having a global object with `settings` that is used everywhere.

This could be especially useful during testing, as it's very easy to override a dependency with your own custom settings.

### The config file { #the-config-file }

Coming from the previous example, your `config.py` file could look like:

   * Builder} constructor.
   */
  public static <E> Builder<E> builder() {
    return new Builder<>();
  }

  /**
   * A builder for creating immutable multiset instances, especially {@code public static final}
   * multisets ("constant multisets"). Example:
   *
   * {@snippet :
   * public static final ImmutableMultiset<Bean> BEANS =
   *     new ImmutableMultiset.Builder<Bean>()

The end result is that the item paths are now:

* `/items/`
* `/items/{item_id}`

...as we intended.

* They will be marked with a list of tags that contain a single string `"items"`.
    * These "tags" are especially useful for the automatic interactive documentation systems (using OpenAPI).
* All of them will include the predefined `responses`.
* All these *path operations* will have the list of `dependencies` evaluated/executed before them.