## Add more validations { #add-more-validations }

You can also add a parameter `min_length`:

{* ../../docs_src/query_params_str_validations/tutorial003_an_py310.py hl[10] *}

## Add regular expressions { #add-regular-expressions }

    }

    @Override
    public int hashCode() {
        return items.hashCode();
    }

    // CHECKSTYLE_OFF: LineLength

    /**
     * Main to test version parsing and comparison.
     * <p>
     * To check how "1.2.7" compares to "1.2-SNAPSHOT", for example, you can issue

app = FastAPI()


@app.get("/items/{item_id}")
def main(
    item_id: int = Path(default=..., gt=0),
    query: str = Query(default=..., max_length=10),
    session: str = Cookie(default=..., min_length=3),
    x_trace: str = Header(default=..., title="Tracing header"),
):
    return {"message": "Hello World"}
```

...all these parameters are required because the default value is `...` (Ellipsis).