The fast food store has 8 processors (cashiers/cooks). While the concurrent burgers store might have had only 2 (one cashier and one cook).

But still, the final experience is not the best. 😞

---

This would be the parallel equivalent story for burgers. 🍔

For a more "real life" example of this, imagine a bank.

# Help FastAPI - Get Help

Do you like **FastAPI**?

Would you like to help FastAPI, other users, and the author?

Or would you like to get help with **FastAPI**?

There are very simple ways to help (several involve just one or two clicks).

And there are several ways to get help too.

## Subscribe to the newsletter

In the Python developer surveys, it's clear <a href="https://www.jetbrains.com/research/python-developers-survey-2017/#tools-and-features" class="external-link" target="_blank">that one of the most used features is "autocompletion"</a>.

The whole **FastAPI** framework is based to satisfy that. Autocompletion works everywhere.

You will rarely need to come back to the docs.

But we also pass a `list` of scopes, in this case with just one scope: `items` (it could have more).

And the dependency function `get_current_active_user` can also declare sub-dependencies, not only with `Depends` but also with `Security`. Declaring its own sub-dependency function (`get_current_user`), and more scope requirements.

In this case, it requires the scope `me` (it could require more than one scope).

!!! note

def examples(
    item: Item = Body(
        examples=[
            {"data": "Data in Body examples, example1"},
        ],
        openapi_examples={
            "Example One": {
                "summary": "Example One Summary",
                "description": "Example One Description",
                "value": {"data": "Data in Body examples, example1"},
            },
            "Example Two": {

            ]
        }
    )


@needs_py39
def test_get_invalid_one_header_items(client: TestClient):
    response = client.get("/items/", headers={"X-Token": "invalid"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "X-Token header invalid"}


@needs_py39
def test_get_invalid_one_users(client: TestClient):

In the next sections you will see other options, configurations, and additional features.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

You could still use most of the features in **FastAPI** with the knowledge from the main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank}.

And the distributed container system with the **load balancer** would **distribute the requests** to each one of the containers with your app **in turns**. So, each request could be handled by one of the multiple **replicated containers** running your app.

    if origin is Union or origin is UnionType:
        at_least_one_scalar_sequence = False
        for arg in get_args(annotation):
            if field_annotation_is_scalar_sequence(arg):
                at_least_one_scalar_sequence = True
                continue
            elif not field_annotation_is_scalar(arg):
                return False
        return at_least_one_scalar_sequence

                    "msg": "field required",
                    "type": "value_error.missing",
                },
            ]
        }
    )


@needs_py39
def test_get_invalid_one_header(client: TestClient):
    response = client.get("/items/", headers={"X-Token": "invalid"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "X-Token header invalid"}