Python has implicit string continuation, so you can do this:
```python
xmodule = (
    "watchmedo shell-command "
    " --patterns='*.js;*.coffee;*.sass;*.scss;*.css' "
    " --recursive "
    " --command=\'xmodule_assets common/static/xmodule\'"
    " --wait "
    " common/lib/xmodule"
)
```
Or reformat as you see fit to make it more readable.