Documentation of Model.from_disk

When I tried literally running

Model().from_disk('saved_model.bin')

I as referenced by the [documentation](https://thinc.ai/docs/api-model#from_disk), I got an error:

```
Traceback (most recent call last):
File "", line 1, in
TypeError: __init__() missing 2 required positional arguments: 'name' and 'forward'
```

So, the documentation needs be updated to note what kind of model instance has to be used for reading from disk. Can I use a generic `Model("unknown", lambda x: None)` or do I need a look-alike model to the one I'm reading?