)
}

func TestMultipleMany2Many(t *testing.T) {
	type Thing struct {
		ID int
	}

	type Person struct {
		ID       int
		Likes    []Thing `gorm:"many2many:likes"`
		Dislikes []Thing `gorm:"many2many:dislikes"`
	}

	checkStructRelation(t, &Person{},
		Relation{
			Name: "Likes", Type: schema.Many2Many, Schema: "Person", FieldSchema: "Thing",
			JoinTable: JoinTable{Name: "likes", Table: "likes"},

* A particular program while it is **running** on the operating system.
    * This doesn't refer to the file, nor to the code, it refers **specifically** to the thing that is being **executed** and managed by the operating system.

In previous versions of NodeJS / Browser JavaScript, you would have used "callbacks". Which leads to <a href="http://callbackhell.com/" class="external-link" target="_blank">callback hell</a>.

## Coroutines

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.

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

I think `Union[SomeType, None]` is more explicit about what it means.

It's just about the words and names. But those words can affect how you and your teammates think about the code.

As an example, let's take this function:

```Python hl_lines="1  4"
{!../../../docs_src/python_types/tutorial009c.py!}

!!! tip
    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

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

```Python hl_lines="14-19"
{!../../../docs_src/events/tutorial003.py!}
```

	//
	// We want to do the same thing in ambient but can't rely on podSpec injection. So, do effectively the same thing,
	// but with iptables rules - use `--socket-exists` as a proxy for "is this a forwarded packet" vs "is this originating from
	// a local node socket". If the latter, outside the pod in the host netns, redirect that traffic to a hardcoded/custom proxy

This is the basic idea. But you will probably want to take care of some additional things, like:

* Security - HTTPS
* Running on startup
* Restarts
* Replication (the number of processes running)
* Memory
* Previous steps before starting

```

!!! tip
    The `callback_url` query parameter uses a Pydantic <a href="https://docs.pydantic.dev/latest/concepts/types/#urls" 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

The actual callback code will depend heavily on your own API app.

effectively just a shim to catch pod creation events and notify the CNI agent early enough to set up network redirection before the pod is fully started. This is necessary because the CNI plugin is effectively the first thing to see a scheduled pod - before the K8S control plane will see things like the pod IP or networking info, the CNI will - but the CNI plugin alone is not sufficient to handle all pod events (already-started pod updates, rebuilding current state on CNI restart) that the node agent cares...