So, if you have an object `something` (that might _not_ be a function) and you can "call" it (execute it) like:

```Python
something()
```

or

```Python
something(some_argument, some_keyword_argument="foo")
```

then it is a "callable".

## Classes as dependencies

You might notice that to create an instance of a Python class, you use that same syntax.

For example:

```Python

!!! info
    OpenAPI 3.1.0 (used since FastAPI 0.99.0) added support for `examples`, which is part of the **JSON Schema** standard.

    Before that, it only supported the keyword `example` with a single example. That is still supported by OpenAPI 3.1.0, but is deprecated and is not part of the JSON Schema standard. So you are encouraged to migrate `example` to `examples`. 🤓

* Fix testing OAuth2 security scopes when using dependency overrides. PR [#1549](https://github.com/tiangolo/fastapi/pull/1549) by [@amacfie](https://github.com/amacfie).
* Fix Model for JSON Schema keyword `not` as a JSON Schema instead of a list. PR [#1548](https://github.com/tiangolo/fastapi/pull/1548) by [@v-do](https://github.com/v-do).

                another one for output.
                """
            ),
        ] = True,
        **extra: Annotated[
            Any,
            Doc(
                """
                Extra keyword arguments to be stored in the app, not used by FastAPI
                anywhere.
                """
            ),
        ],
    ) -> None:
        self.debug = debug
        self.title = title