How to list all files been tracked by git?

Hey all,

How do I get a list of all file? using git I can run 
```bash
git ls-tree HEAD -r
```

how can I do it with this library? the best I could find is:
```python
for file in repo.commit().tree.blobs:
    print(file.abspath)
```
but that only lists files in the top dictionary.

Thanks