In my site.py
I just need to import webassets. I'm using the flask flavor but there's one for every major python framework.
https://webassets.readthedocs.org/en/latest/
from flask.ext.assets import Environment, Bundle
Then in my base.html
for sass/compass and css minification I have a filter like this:
{% assets filters='compass,scss,cssmin', depends='styles/**/*.scss', output='styles/site.min.css', 'styles/site.scss'%}
<link rel="stylesheet" type="text/css" href="{{ ASSET_URL }}">
{% endassets %}