Marking section completed

I am a retired life-long learner going thru a Khan academy class purely for my own enrichment.  I'm not part of any formal class.  If Khan academy fails to mark a section completed even after I have been thru the material, I would like to have it so marked so that I do not inadvertently repeat it if I come back to it later.  I'm doing this for myself so I am not cheating any educational overseer.  I just want to have it marked complete so that I have record of it.  Is there a way to do this?