Might be a bit clearer to break this up:
```python
handouts_li = [
    '<li><a href="/static/{handout}">Example Handout</a></li>'.format(handout=handout)
    for handout in self._handouts
]
handouts_html = '<ol class="treeview-handoutsnav">{}</ol>'.format("".join(handouts_li))
```