I think everyone has the capacity to be funny in their own way. Learning to be funny the "conventional" way won't work if it's not compatible with your personality. The only thing they can study is their own capacity for humour, because there's plenty of ways to train that. Dark humour might work for one person, while sarcasm and dry-humour works for another, and boisterous Robin Williams-Jim Carrey humour can work for someone else. Just get to know who you are and what works best for you.