Quote from PEP 8 -
When in doubt, use your best judgment. Look at other examples and decide what looks best.
This boils down to you i.e. the current project. It is actually a matter of personal choice. The PEP 8 or any other styleguide is basically, a guide. You'll have to judge as to what goes better with your situation.
Specific points that would matter, which I would like to mention are -
- Do you have a lot a acronyms that would be used?
- What is your project team comfortable with?
And, like I mentioned in my comment, using lower_case_with_underscores
helps differentiate Twisted
modules & your custom modules/functions.