## Future { #future }

By this point, it's already clear that **FastAPI** with its ideas is being useful for many people.

It is being chosen over previous alternatives for suiting many use cases better.

	...
</pre>

<p>
This is the list of instructions and their spellings as known to the assembler and linker for that architecture.
Each instruction begins with an initial capital <code>A</code> in this list, so <code>AAND</code>
represents the bitwise and instruction,
<code>AND</code> (without the leading <code>A</code>),
and is written in assembly source as <code>AND</code>.
The enumeration is mostly in alphabetical order.

and what the program that uses the Library does.

  1. You may copy and distribute verbatim copies of the Library's
complete source code as you receive it, in any medium, provided that
you conspicuously and appropriately publish on each copy an
appropriate copyright notice and disclaimer of warranty; keep intact
all the notices that refer to this License and to the absence of any

		desc. If you want to find documents which has "Fess" and sort them in
		descending order, you can enter:
		<pre>Fess sort:content_length.desc</pre>
		The available sort field are "created", "content_length" and
		"last_modified", and they are customizable.
	</dd>
	<dt>AND</dt>
	<dd>
		AND operator is the default conjunction operator. You can omit it from
		a query. AND operator matches documents where both terms exist

Without types, that's almost impossible to achieve.

Notice that the variable `item` is one of the elements in the list `items`.

And still, the editor knows it is a `str`, and provides support for that.

#### Tuple and Set { #tuple-and-set }

You would do the same to declare `tuple`s and `set`s:

//// tab | Python 3.9+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial007_py39.py!}
```

////

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters { #mix-path-query-and-body-parameters }

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

And you can also declare body parameters as optional, by setting the default to `None`:

But if you need to access variables and objects from the same **FastAPI** app, or you need to perform small background tasks (like sending an email notification), you can simply just use `BackgroundTasks`.

## Recap { #recap }

#### Shared reader thread

## Reporting a Vulnerability

If you think you found a vulnerability, and even if you are not sure about it, please report it right away by sending an email to: ******@****.***. Please try to be as explicit as possible, describing all the steps and example code to reproduce the security issue.

## Sub-dependencies with `yield` { #sub-dependencies-with-yield }

You can have sub-dependencies and "trees" of sub-dependencies of any size and shape, and any or all of them can use `yield`.

**FastAPI** will make sure that the "exit code" in each dependency with `yield` is run in the correct order.

For example, `dependency_c` can have a dependency on `dependency_b`, and `dependency_b` on `dependency_a`: