We are going to include this `APIRouter` in the main `FastAPI` app, but first, let's check the dependencies and another `APIRouter`.

## Dependencies

We see that we are going to need some dependencies used in several places of the application.

So we put them in their own `dependencies` module (`app/dependencies.py`).

        // If we are at a super-type constructor call, adjust the resolution expression so that we
        // get the constructor instead of the class.
        //
        // For the example:
        //
        // class A {
        //   constructor()
        // }
        // class B: <caret>A()
        //

 that currently we have information about a project scattered across the project.xml and the
 various properties files. What needs to be done is to encapsulate all of this in the POM.

 Typically users parameterize the use of plugins, or have custom values like ${user.name}
 for use in elements like the <developerConnection/>. It would be idea if we

    //     we find them, regardless of what the address policies need.
    //
    //  2. EVICTABLE: Connections not required by any address policy. This matches connections that
    //     don't participate in any policy, plus connections whose policies won't be violated if the
    //     connection is closed. We only close these if the idle connection limit is exceeded.
    //

        }

        if (errorExceptionToDeliver != null) {
          // We defer throwing the exception until now so that we can refill the connection
          // flow-control window. This is necessary because we don't transmit window updates until
          // the application reads the data. If we throw this prior to updating the connection
          // flow-control window, we risk having it go to 0 preventing the server from sending data.

We can use **OAuth2** to build that with **FastAPI**.

But let's save you the time of reading the full long specification just to find those little pieces of information you need.

Let's use the tools provided by **FastAPI** to handle security.

## How it looks

Let's first just use the code and see how it works, and then we'll come back to understand what's happening.

We can also use this same approach to access the request body in an exception handler.

All we need to do is handle the request inside a `try`/`except` block:

```Python hl_lines="13  15"
{!../../../docs_src/custom_request_and_route/tutorial002.py!}
```

If an exception occurs, the`Request` instance will still be in scope, so we can read and make use of the request body when handling the error:

    "completed": False,
}
```

but it doesn't have the `id` field.

So we create a new `dict`, that contains the key-value pairs from `note.dict()` with:

```Python
{**note.dict()}
```

`**note.dict()` "unpacks" the key value pairs directly, so, `{**note.dict()}` would be, more or less, a copy of `note.dict()`.

And then, we extend that copy `dict`, adding another key-value pair: `"id": last_record_id`:

```Python

Istio consumes _many_ different types of clients (at the time of writing, 7), as well as informers for each of these.
Additionally, we often need to convert to various different client forms for different libraries we integrate with.

`kube.Client` just bundles these all in one place, so we have a single object to pass around anywhere we need Kubernetes access.
Additionally, it has a fake client variant, that does the same thing but with fake clients for use in unit tests.

### We Make Mistakes

We, as humans, make **mistakes**, all the time. Software almost *always* has **bugs** hidden in different places. 🐛

And we as developers keep improving the code as we find those bugs and as we implement new features (possibly adding new bugs too 😅).

### Small Errors Automatically Handled