I'm not, it's poor name for that function (see current.py in master, it does the same thing).  `to_notebook_json` is actually the `to_notebook` function in the *vX\nbjson.py* file (where vX = v2, 3 etc..)  See snippet from code in master:

```python
class JSONReader(NotebookReader):

    def reads(self, s, **kwargs):
        nb = json.loads(s, **kwargs)
        nb = self.to_notebook(nb, **kwargs)
        return nb

    def to_notebook(self, d, **kwargs):
        return rejoin_lines(from_dict(d))
```

It really is just rejoining the code lines.  Should I rename this in this PR?