</blockquote>

## Investigação

Ao usar todas as alternativas anteriores, eu tive a chance de aprender com todas elas, aproveitar ideias e combiná-las da melhor maneira que encontrei para mim e para os times de desenvolvedores com os quais trabalhava.

### Tested

* 100% <abbr title="The amount of code that is automatically tested">test coverage</abbr>.
* 100% <abbr title="Python type annotations, with this your editor and external tools can give you better support">type annotated</abbr> code base.
* Used in production applications.

## Starlette features

### 💯

* 1️⃣0️⃣0️⃣ 💯 <abbr title="The amount of code that is automatically tested">💯 💰</abbr>.
* 1️⃣0️⃣0️⃣ 💯 <abbr title="Python type annotations, with this your editor and external tools can give you better support">🆎 ✍</abbr> 📟 🧢.
* ⚙️ 🏭 🈸.

## 💃 ⚒

    {!> ../../../docs_src/dependencies/tutorial001.py!}
    ```

Although you use `Depends` in the parameters of your function the same way you use `Body`, `Query`, etc, `Depends` works a bit differently.

You only give `Depends` a single parameter.

This parameter must be something like a function.

You **don't call it** directly (don't add the parenthesis at the end), you just pass it as a parameter to `Depends()`.

### Suggest solutions

* After being able to understand the question, you can give them a possible **answer**.

* In many cases, it's better to understand their **underlying problem or use case**, because there might be a better way to solve it than what they are trying to do.

### Ask to close

!!! note
    FastAPI will know that the value of `q` is not required because of the default value `= None`.

    The `Union` in `Union[str, None]` will allow your editor to give you better support and detect errors.

## Additional validation

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

                                            {
                                                "name": "Baz",
                                                "price": "thirty five point four",
                                            },
                                        ],
                                    }
                                )
                                | IsDict(

                                            {
                                                "name": "Baz",
                                                "price": "thirty five point four",
                                            },
                                        ],
                                    }
                                )
                                | IsDict(

            },
            "invalid": {
                "summary": "Invalid data is rejected with an error",
                "value": {
                    "name": "Baz",
                    "price": "thirty five point four",
                },
            },
        },
    ),
):
    results = {"item_id": item_id, "item": item}

# Advanced User Guide

## Additional Features

The main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} should be enough to give you a tour through all the main features of **FastAPI**.

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.