For example, this is not allowed:

```Python
q: Annotated[str, Query(default="rick")] = "morty"
```

...because it's not clear if the default value should be `"rick"` or `"morty"`.

So, you would use (preferably):

```Python
q: Annotated[str, Query()] = "rick"
```

...or in older code bases you will find:

```Python

```Python
from fastapi import Depends, FastAPI, HTTPException
from typing_extensions import Annotated

app = FastAPI()


data = {
    "plumbus": {"description": "Freshly pickled plumbus", "owner": "Morty"},
    "portal-gun": {"description": "Gun to create portals", "owner": "Rick"},
}


class OwnerError(Exception):
    pass


def get_username():
    try:
        yield "Rick"