The easiest way to look for cheetah I think is to just look for a cheetah downvote on that post. Should be possible to look for the comment too but I haven't tired either myself yet. I know others do check for the vote though. Has to be a simple command to list all votes on a post or steemit would take forever to scan the user history every time you click the voting history. I'll try to check tomorrow if I have the time. Too much spam to wade though tonight.

Edit: Forgot I still had the docs open. Piston has a get_comments() function that returns all top level comments so there you go. p=Post("@author/permlink"). If cheetah or steemcleaners in p.get_comments(). I would assume p would contain the list of votes as well.