index = index,
    token = token
)

/**
 * Implicit dispatch receiver is present when an extension function declared in object
 * is imported somewhere else and used without directly referencing the object instance
 * itself:
 *
 * ```kt
 * import Foo.bar
 *
 * object Foo { fun String.bar() {} }
 *
 * fun usage() {

import "k8s.io/apimachinery/pkg/runtime/schema/generated.proto";

// Package-wide variables from generator "generated".
option go_package = "k8s.io/api/events/v1beta1";

// Event is a report of an event somewhere in the cluster. It generally denotes some state change in the system.
// Events have a limited retention time and triggers and messages may evolve
// with time.  Event consumers should not rely on the timing of an event

You also define in some way at which **moments** your app will send those requests or events.

And **your users** define in some way (for example in a web dashboard somewhere) the **URL** where your app should send those requests.

All the **logic** about how to register the URLs for webhooks and the code to actually send those requests is up to you. You write it however you want to in **your own code**.

    ```

### Return values

And they can return values or not, the values won't be used.

So, you can re-use a normal dependency (that returns a value) you already use somewhere else, and even though the value won't be used, the dependency will be executed:

=== "Python 3.9+"

    ```Python hl_lines="11  16"
    {!> ../../../docs_src/dependencies/tutorial006_an_py39.py!}
    ```

import "k8s.io/apimachinery/pkg/runtime/schema/generated.proto";

// Package-wide variables from generator "generated".
option go_package = "k8s.io/api/events/v1";

// Event is a report of an event somewhere in the cluster. It generally denotes some state change in the system.
// Events have a limited retention time and triggers and messages may evolve
// with time.  Event consumers should not rely on the timing of an event

```sh
[req]
distinguished_name = req_distinguished_name
x509_extensions = v3_req
prompt = no

[req_distinguished_name]
C = US
ST = VA
L = Somewhere
O = MyOrg
OU = MyOU
CN = MyServerName

[v3_req]
subjectAltName = @alt_names

[alt_names]
IP.1 = 127.0.0.1
DNS.1 = localhost
```

        * And if the token is stolen, the risk is less. It is not like a permanent key that will work forever (in most of the cases).
* The frontend stores that token temporarily somewhere.
* The user clicks in the frontend to go to another section of the frontend web app.
* The frontend needs to fetch some more data from the API.
    * But it needs authentication for that specific endpoint.

common_parameters --> read_users
```

This way you write shared code once and **FastAPI** takes care of calling it for your *path operations*.

!!! check
    Notice that you don't have to create a special class and pass it somewhere to **FastAPI** to "register" it or anything similar.

    You just pass it to `Depends` and **FastAPI** knows how to do the rest.

## Share `Annotated` dependencies

* **Coroutines**

## Asynchronous Code

Asynchronous code just means that the language 💬 has a way to tell the computer / program 🤖 that at some point in the code, it 🤖 will have to wait for *something else* to finish somewhere else. Let's say that *something else* is called "slow-file" 📝.

So, during that time, the computer can go and do some other work, while "slow-file" 📝 finishes.

even if I fell off the top of the house!' (Which was very likely
true.)

  Down, down, down.  Would the fall NEVER come to an end!  `I
wonder how many miles I've fallen by this time?' she said aloud.
`I must be getting somewhere near the centre of the earth.  Let
me see:  that would be four thousand miles down, I think--' (for,
you see, Alice had learnt several things of this sort in her
lessons in the schoolroom, and though this was not a VERY good