<img src="/img/python-types/image04.png">

Now you know that you have to fix it, convert `age` to a string with `str(age)`:

{* ../../docs_src/python_types/tutorial004_py39.py hl[2] *}

## Declaring types { #declaring-types }

You just saw the main place to declare type hints. As function parameters.

URLs (like `https://github.com/square/okhttp`) are fundamental to HTTP and the Internet. In addition to being a universal, decentralized naming scheme for everything on the web, they also specify how to access web resources.

URLs are abstract:

```JSON
{"item_id":3}
```

/// check | Testen

Beachten Sie, dass der Wert, den Ihre Funktion erhält und zurückgibt, die Zahl `3` ist, also ein `int`. Nicht der String `"3"`, also ein `str`.

Also, before that, in previous versions, the `request` object was passed as part of the key-value pairs in the context for Jinja2.

///

/// tip

By declaring `response_class=HTMLResponse` the docs UI will be able to know that the response will be HTML.

///

/// note | Technical Details

You could also use `from starlette.templating import Jinja2Templates`.

# Using Dataclasses { #using-dataclasses }

FastAPI is built on top of **Pydantic**, and I have been showing you how to use Pydantic models to declare requests and responses.

But FastAPI also supports using <a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a> the same way:

{* ../../docs_src/dataclasses_/tutorial001_py310.py hl[1,6:11,18:19] *}

Follow your cloud provider's guides to deploy FastAPI apps with them. 🤓

## Deploy your own server { #deploy-your-own-server }

    assertFailsWith<IllegalArgumentException> {
      windowUpdate(0)
    }.also { expected ->
      assertThat(expected.message)
        .isEqualTo("windowSizeIncrement == 0 || windowSizeIncrement > 0x7fffffffL: 0")
    }
    assertFailsWith<IllegalArgumentException> {
      windowUpdate(0x80000000L)
    }.also { expected ->
      assertThat(expected.message)

# GraphQL { #graphql }

As **FastAPI** is based on the **ASGI** standard, it's very easy to integrate any **GraphQL** library also compatible with ASGI.

You can combine normal FastAPI *path operations* with GraphQL on the same application.

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

///

/// note | Technical Details

You could also use `from starlette.requests import Request`.

**FastAPI** provides it as a convenience for you, the developer. But it comes directly from Starlette.

///

### Before and after the `response` { #before-and-after-the-response }

You can add code to be run with the `request`,  before any *path operation* receives it.

And also after the `response` is generated, before returning it.

    /**
     * Indicates whether Maven should also build the specified projects' dependencies.
     *
     * @return an {@link Optional} containing true if dependencies should also be built, false if not, or empty if not specified
     */
    @Nonnull
    Optional<Boolean> alsoMake();

    /**
     * Indicates whether Maven should also build the specified projects' dependents.
     *