We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

A "**callable**" in Python is anything that Python can "call" like a function.

      Runnable task, @ParametricNullness T result);

  /**
   * {@inheritDoc}
   *
   * <p>All elements in the returned list must be {@link ListenableFuture} instances. The easiest
   * way to obtain a {@code List<ListenableFuture<T>>} from this method is an unchecked (but safe)
   * cast:
   *
   * <pre>
   *   {@code @SuppressWarnings("unchecked") // guaranteed by invokeAll contract}

   * or extract a variable, and put the suppression on that. However, a local variable typically
   * doesn't work: Because nullness analyses typically infer the nullness of local variables,
   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.

    /**
     * Retrieve all addresses of a host by it's address. NetBIOS hosts can
     * have many names for a given IP address. The name and IP address make the
     * NetBIOS address. This provides a way to retrieve the other names for a
     * host with the same IP address.
     *
     * @param addr
     *            the address to query
     * @return resolved addresses
     * @throws UnknownHostException

Import `File` and `UploadFile` from `fastapi`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[3] *}

## Define `File` Parameters { #define-file-parameters }

Create file parameters the same way you would for `Body` or `Form`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[9] *}

/// info

`File` is a class that inherits directly from `Form`.

# Cookie Parameters { #cookie-parameters }

You can define Cookie parameters the same way you define `Query` and `Path` parameters.

## Import `Cookie` { #import-cookie }

First import `Cookie`:

{* ../../docs_src/cookie_params/tutorial001_an_py310.py hl[3] *}

## Declare `Cookie` parameters { #declare-cookie-parameters }

Then declare the cookie parameters using the same structure as with `Path` and `Query`.

```

The parameter values in your function will be:

* `skip=20`: because you set it in the URL
* `limit=10`: because that was the default value

## Optional parameters { #optional-parameters }

The same way, you can declare optional query parameters, by setting their default to `None`:

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

 limitations under the License.
-->
Contributing to Apache Maven
======================

You have found a bug or you have an idea for a cool new feature? Contributing
code is a great way to give something back to the open source community. Before
you dig right into the code, there are a few guidelines that we need
contributors to follow so that we can have a chance of keeping on top of
things.

the potential to leak sensitive information such as "Authorization" or "Cookie" headers and the
contents of request and response bodies. This data should only be logged in a controlled way or in
a non-production environment.

You can redact headers that may contain sensitive information by calling `redactHeader()`.
```java
logging.redactHeader("Authorization");
logging.redactHeader("Cookie");
```

/// warning

The recommended way to handle the *startup* and *shutdown* is using the `lifespan` parameter of the `FastAPI` app as described above. If you provide a `lifespan` parameter, `startup` and `shutdown` event handlers will no longer be called. It's all `lifespan` or all events, not both.

You can probably skip this part.

///