I didn't check. I have an "I think" in there because it was my personal opinion after spending a few minutes thinking about it after reading the title of this A

I didn't check. I have an "I think" in there because it was my personal opinion after spending a few minutes thinking about it after reading the title of this Ask HN thread. It was interesting because it made me think "that's true, why don't we have them?" so I replied.