The exception handler will receive a `Request` and the exception.

```Python hl_lines="2  14-16"
{!../../../docs_src/handling_errors/tutorial004.py!}
```

Now, if you go to `/items/foo`, instead of getting the default JSON error with:

```JSON
{
    "detail": [
        {
            "loc": [
                "path",
                "item_id"
            ],