The truly weird thing here is that [] + (2,) is a TypeError: can only concatenate list (not "tuple") to list but L = [] L += (2,) is totally c

The truly weird thing here is that [] + (2,) is a TypeError: can only concatenate list (not "tuple") to list but L = [] L += (2,) is totally cool. In the end, it makes sense because I can't tell you if []+() should be a tuple or a list, and even if I did, I might have a different answer for ()+[]; whereas L+=bla looks like the type of L should not change.