I had a racket exam last week and I named some of my methods for the exam using the question mark symbol(e.g. "belongs?", "has-fever?", etc...). But when they gave me the results, one of my professors told me that it's a bad practice to use the "?" in methods in the way that I used it and I don't get it because a lot of methods in racket are originally called like that.
So my question is: is it really a bad practice or is it not? and if it is a bad practice, why racket use it?
According to the Racket codebase's own Style Guide predicates and boolean-valued functions should end in ?. belongs? and has-fever? seem to fit that bill, so I suspect this is down to your professor's taste.