### Create a dependency, or "dependable" { #create-a-dependency-or-dependable }

Let's first focus on the dependency.

It is just a function that can take all the same parameters that a *path operation function* can take:

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[8:9] *}

That's it.

**2 lines**.

And it has the same shape and structure that all your *path operation functions* have.

For this, use the Python standard module <a href="https://docs.python.org/3/library/secrets.html" class="external-link" target="_blank">`secrets`</a> to check the username and password.

`secrets.compare_digest()` needs to take `bytes` or a `str` that only contains ASCII characters (the ones in English), this means it wouldn't work with characters like `á`, as in `Sebastián`.

### FastAPI Data Filtering { #fastapi-data-filtering }

Now, for FastAPI, it will see the return type and make sure that what you return includes **only** the fields that are declared in the type.

Instead of that, by being an "asynchronous" system, once finished, the task can wait in line a little bit (some microseconds) for the computer / program to finish whatever it went to do, and then come back to take the results and continue working with them.

   *
   * @param eventClass a class to assert that the returned event is an instance of, or null to
   *     take any event class.
   * @param elapsedMs the time in milliseconds elapsed since the immediately-preceding event, or
   *     -1L to take any duration.
   */
  fun takeEvent(
    eventClass: Class<out CallEvent>? = null,
    elapsedMs: Long = -1L,
  ): CallEvent {

      // we allow one second worth of work to go in a burst (i.e. take less than a second)
      assertThat(burst).isAtMost(1000);
      long afterBurst = measureTotalTimeMillis(limiter, oneSecWorthOfWork, new Random());
      // but work beyond that must take at least one second
      assertThat(afterBurst).isAtLeast(1000);
    }
  }

  /**

      // we allow one second worth of work to go in a burst (i.e. take less than a second)
      assertThat(burst).isAtMost(1000);
      long afterBurst = measureTotalTimeMillis(limiter, oneSecWorthOfWork, new Random());
      // but work beyond that must take at least one second
      assertThat(afterBurst).isAtLeast(1000);
    }
  }

  /**

Here you saw how to use multiple **workers** to **parallelize** the execution of the application, take advantage of **multiple cores** in the CPU, and be able to serve **more requests**.

From the list of deployment concepts from above, using workers would mainly help with the **replication** part, and a little bit with the **restarts**, but you still need to take care of the others:

* **Security - HTTPS**
* **Running on startup**
* ***Restarts***

 * This form extends CreateForm to include fields necessary for updating existing stemmer override entries.
 * Stemmer overrides define custom stemming rules that take precedence over the default stemming algorithm.
 *
 */
public class EditForm extends CreateForm {

    /**
     * Creates a new EditForm instance.
     */
    public EditForm() {
        super();
    }

You can deploy your FastAPI app to <a href="https://fastapicloud.com" class="external-link" target="_blank">FastAPI Cloud</a> with **one command**, go and join the waiting list if you haven't. 🚀

## Login { #login }

Make sure you already have a **FastAPI Cloud** account (we invited you from the waiting list 😉).

Then log in:

<div class="termy">

```console
$ fastapi login

You are logged in to FastAPI Cloud 🚀
```