Match on 2d list ?

Hi, thanks for the very interesting work. 
Is matching 2d lists supported ?
Example:

```python
match([['a', 1, 2], ['b', 3, 4], ['a', 5, 6]], ['a', _, _], lambda x, y : [x, y])
```

expecting 

```python
[[1, 2], [5, 6]]
```