It's syntax sugar. I use it all the time, but of course it could always be respected by, i don't know, a for loop. It also makes writing duck typed code easier,

It's syntax sugar. I use it all the time, but of course it could always be respected by, i don't know, a for loop. It also makes writing duck typed code easier, as X3 will work for strings, bytes and lists. Overall it's a very useful feature and I don't think it's that surprising. It's pretty obvious [x]4 will reuse the same reference. Just like manually adding "x" four times will.