```

### Check the docs

Because the available values for the *path parameter* are predefined, the interactive docs can show them nicely:

<img src="/img/tutorial/path-params/image03.png">

### Working with Python *enumerations*

The value of the *path parameter* will be an *enumeration member*.

#### Compare *enumeration members*

You can compare it with the *enumeration member* in your created enum `ModelName`:

 <font color="#4E9A06">╭─────────── FastAPI CLI - Production mode ───────────╮</font>
 <font color="#4E9A06">│                                                     │</font>
 <font color="#4E9A06">│  Serving at: http://0.0.0.0:8000                    │</font>
 <font color="#4E9A06">│                                                     │</font>
 <font color="#4E9A06">│  API docs: http://0.0.0.0:8000/docs                 │</font>

 <span style="background-color:#C4A000"><font color="#2E3436">│                                                     │</font></span>
 <span style="background-color:#C4A000"><font color="#2E3436">│  Serving at: http://127.0.0.1:8000                  │</font></span>
 <span style="background-color:#C4A000"><font color="#2E3436">│                                                     │</font></span>

    Using a relative URL is important to make sure your application keeps working even in an advanced use case like [Behind a Proxy](../../advanced/behind-a-proxy.md){.internal-link target=_blank}.

The client will get a **500 Internal Server Error** for that request, but the application will continue working for the next requests instead of just crashing completely.

### Bigger Errors - Crashes

Nevertheless, there might be cases where we write some code that **crashes the entire application** making Uvicorn and Python crash. 💥

* Add external link [Machine learning model serving in Python using FastAPI and Streamlit](https://davidefiocco.github.io/2020/06/27/streamlit-fastapi-ml-serving.html) to docs. PR [#1669](https://github.com/tiangolo/fastapi/pull/1669) by [@davidefiocco](https://github.com/davidefiocco).

```

!!! tip
    🏗 🔢 👈 🕴 💡 🔗 ⏮️ 💽 (🤚 👩‍💻 ⚖️ 🏬) 🔬 👆 *➡ 🛠️ 🔢*, 👆 💪 🌖 💪 ♻ 👫 💗 🍕 &amp; 🚮 <abbr title="Automated tests, written in code, that check if another piece of code is working correctly.">⚒ 💯</abbr> 👫.

### ✍ 💽

🔜 ✍ 🚙 🔢 ✍ 💽.

🔁:

* ✍ 🇸🇲 🏷 *👐* ⏮️ 👆 📊.
* `add` 👈 👐 🎚 👆 💽 🎉.
* `commit` 🔀 💽 (👈 👫 🖊).

    But because **FastAPI** is based on the Python standards, including `Annotated`, you can use this trick in your code. 😎

The dependencies will keep working as expected, and the **best part** is that the **type information will be preserved**, which means that your editor will be able to keep providing you with **autocompletion**, **inline errors**, etc. The same for other tools like `mypy`.

<div class="termy">

```console
$ python ./scripts/docs.py live

<span style="color: green;">[INFO]</span> Serving on http://127.0.0.1:8008
<span style="color: green;">[INFO]</span> Start watching changes
<span style="color: green;">[INFO]</span> Start detecting changes
```

</div>

 <span style="background-color:#C4A000"><font color="#2E3436">│                                                     │</font></span>
 <span style="background-color:#C4A000"><font color="#2E3436">│  Serving at: http://127.0.0.1:8000                  │</font></span>
 <span style="background-color:#C4A000"><font color="#2E3436">│                                                     │</font></span>