```Python hl_lines="1  15"
{!../../docs_src/debugging/tutorial001.py!}
```

### About `__name__ == "__main__"`

The main purpose of the `__name__ == "__main__"` is to have some code that is executed when your file is called with:

<div class="termy">

```console
$ python myapp.py
```

</div>

but is not called when another file imports it, like in:

```Python

/**
 * Collects, flattens and resolves dependencies.
 */
@Experimental
public interface DependencyResolver extends Service {

    /**
     * Collects the transitive dependencies of some artifacts and builds a dependency graph for the given path scope.
     * Note that this operation is only concerned about determining the coordinates of the transitive dependencies and
     * does not actually resolve the artifact files.

# Support

Here are some resources to help you understand and use Istio:

- For in-depth information about how to use Istio, visit [istio.io](https://istio.io)
- To ask questions and get assistance from our community, visit [GitHub Discussions](https://github.com/istio/istio/discussions)

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

Make sure you evaluate if the **benefits** for your use case compensate the **drawbacks**. 🤓

///

## GraphQL Libraries

Here are some of the **GraphQL** libraries that have **ASGI** support. You could use them with **FastAPI**:

     * is given by {@link #getSource()}.
     *
     * @return The one-based index of the line containing the problem or a non-positive value if unknown.
     */
    int getLineNumber();

    /**
     * Gets the one-based index of the column containing the problem. The column number should refer to some text file
     * that is given by {@link #getSource()}.
     *

    * This is particularly important for **security**, we'll see more of that below.

## `response_model` Parameter

There are some cases where you need or want to return some data that is not exactly what the type declares.

The way you use it is very simple. For example, to do a `GET` request, you would write:

```Python
response = requests.get("http://example.com/some/url")
```

The FastAPI counterpart API *path operation* could look like:

```Python hl_lines="1"
@app.get("/some/url")
def read_url():
    return {"message": "Hello World"}
```

See the similarities in `requests.get(...)` and `@app.get(...)`.

    if model_name.value == "lenet":
        return {"model_name": model_name, "message": "LeCNN all the images"}

* Great editor support.
* Data conversion from incoming requests.
* Data conversion for response data.
* Data validation.
* Automatic annotation and documentation.

## Other data types

Here are some of the additional data types you can use:

* `UUID`:
    * A standard "Universally Unique Identifier", common as an ID in many databases and systems.
    * In requests and responses will be represented as a `str`.

     * is given by {@link #getSource()}.
     *
     * @return the one-based index of the line containing the problem or a non-positive value if unknown
     */
    int getLineNumber();

    /**
     * Gets the one-based index of the column containing the problem. The column number should refer to some text file
     * that is given by {@link #getSource()}.
     *