We have only loosely enforced these stylistic guidelines in the past, it seems. Can't fault you for copying merged code! The Lab routines probably should be changed, though. You could make a separate PR to do that, or file an issue and someone will do it.

From CONTRIBUTING.txt:

```
When documenting array parameters, use ``image : (M, N) ndarray``
and then refer to ``M`` and ``N`` in the docstring, if necessary.
```