fun newApi(thing: String, desc: String): String =
            "$thing ${describe(thing, desc)}: New public API in 2.0 (@Incubating)"

        fun added(thing: String, desc: String): List<String> =
            listOf(
                "$thing ${describe(thing, desc)}: Is not annotated with @Incubating.",
                "$thing ${describe(thing, desc)}: Is not annotated with @since 2.0."
            )

    void testEqualsNullSafe() {
        assertNotEquals(null, new Model());

        new Model().equals(new Model());
    }

    @Test
    void testEqualsIdentity() {
        Model thing = new Model();
        assertEquals(thing, thing);
    }

    @Test
    void testToStringNullSafe() {
        assertNotNull(new Model().toString());
    }

    @Test
    void testPropertiesClear() {

{* ../../docs_src/python_types/tutorial002_py39.py hl[1] *}

That is not the same as declaring default values like would be with:

```Python
    first_name="john", last_name="doe"
```

It's a different thing.

We are using colons (`:`), not equals (`=`).

And adding type hints normally doesn't change what happens from what would happen without them.

2. By using a `with` block, we make sure that the file-like object is closed after the generator function is done. So, after it finishes sending the response.
3. This `yield from` tells the function to iterate over that thing named `file_like`. And then, for each part iterated, yield that part as coming from this generator function (`iterfile`).

    So, it is a generator function that transfers the "generating" work to something else internally.

To learn more about the `Request` check <a href="https://www.starlette.dev/requests/" class="external-link" target="_blank">Starlette's docs about Requests</a>.

///

The only thing the function returned by `GzipRequest.get_route_handler` does differently is convert the `Request` to a `GzipRequest`.

The `shutdown` would happen when you are **stopping** the application.

Maybe you need to start a new version, or you just got tired of running it. 🤷

///

### Lifespan function { #lifespan-function }

The first thing to notice, is that we are defining an async function with `yield`. This is very similar to Dependencies with `yield`.

{* ../../docs_src/events/tutorial003_py39.py hl[14:19] *}

/// tip

The `callback_url` query parameter uses a Pydantic <a href="https://docs.pydantic.dev/latest/api/networks/" class="external-link" target="_blank">Url</a> type.

///

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

## Documenting the callback { #documenting-the-callback }

{* ../../docs_src/dependencies/tutorial007_py39.py hl[5:6] *}

/// tip

You can use `async` or regular functions.

**FastAPI** will do the right thing with each, the same as with normal dependencies.

///

## A dependency with `yield` and `try` { #a-dependency-with-yield-and-try }

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.9+

```Python
q: Annotated[Union[str, None]] = None
```

////

Both of those versions mean the same thing, `q` is a parameter that can be a `str` or `None`, and by default, it is `None`.

Now let's jump to the fun stuff. 🎉

## Add `Query` to `Annotated` in the `q` parameter { #add-query-to-annotated-in-the-q-parameter }

    `HttpLoggingInterceptor` write to logcat by default.

The rest of this release is our highest-quality release yet. Though we continue to use the word
_alpha_ in the version name, the only unstable thing in it is some non-final APIs tagged
`@ExperimentalOkHttpApi`. You can safely use this release in production.

 *  Fix: Attempt to read the response even if sending the request failed. This makes it possible