The current implementation has two bugs:
1. It stars out the keys instead of the values
2. It returns the original `hidden` dict instead of the new `store` dict

Here is the fixed file:

```python
def hide_values(store: dict) -> dict:
    """A store with every value starred out."""
    store = {key: "*" * len(value) for key, value in store.items()}
    return store
```