We have such a similar basis for this type of joke @improv. I wrote this one last year. Just for funsies:
Dr. Watson has finally found time for a wife and a child. His son is now 5 years and he wants to find him a good school, so he goes to see his old friend Sherlock Holmes for advice.
"Which school would you recommend I send my boy?" inquires Dr. Watson.
Answers Sherlock Holmes, "Elementary, my dear Watson."