## Dependencies with `yield` and `HTTPException`

You saw that you can use dependencies with `yield` and have `try` blocks that catch exceptions.

The same way, you could raise an `HTTPException` or similar in the exit code, after the `yield`.

!!! tip

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Next it will convert and validate the data. So, when you use that `settings` object, you will have data of the types you declared (e.g. `items_per_user` will be an `int`).

### Use the `settings`

Then you can use the new `settings` object in your application:

```Python hl_lines="18-20"
{!../../../docs_src/settings/tutorial001.py!}
```

### Run the server

**FastAPI** doesn't require you to use a SQL (relational) database.

But you can use any relational database that you want.

Here we'll see an example using <a href="https://www.sqlalchemy.org/" class="external-link" target="_blank">SQLAlchemy</a>.

You can easily adapt it to any database supported by SQLAlchemy, like:

* PostgreSQL
* MySQL
* SQLite

thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions: (a) You must give any other recipients of the Work or Derivative Works a copy of this License; and (b) You must cause any modified files to carry prominent notices stating that You changed the files; and (c) You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the...

## Classes as dependencies

You might notice that to create an instance of a Python class, you use that same syntax.

For example:

```Python
class Cat:
    def __init__(self, name: str):
        self.name = name


fluffy = Cat(name="Mr Fluffy")
```

In this case, `fluffy` is an instance of the class `Cat`.

And to create `fluffy`, you are "calling" `Cat`.

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Recap

In summary, you declare **once** the types of parameters, body, etc. as function parameters.

You do that with standard modern Python types.

You don't have to learn a new syntax, the methods or classes of a specific library, etc.

Just standard **Python 3.8+**.

For example, for an `int`:

This may help you better understand and contribute to Gradle.

### Debugging Gradle

You can debug Gradle by adding `-Dorg.gradle.debug=true` to the command-line. Gradle will wait for you to attach a debugger at `localhost:5005` by default.

If you made changes to build logic in the `build-logic` included build, you can run its tests by executing `./gradlew :build-logic:check`.

If your application is **simple**, this will probably **not be a problem**, and you might not need to specify hard memory limits. But if you are **using a lot of memory** (for example with **machine learning** models), you should check how much memory you are consuming and adjust the **number of containers** that runs in **each machine** (and maybe add more machines to your cluster).

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You
      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices