All elements of both sets or sequences are returned. All elements common to both sets or sequences are returned. All elements of the first set or sequence not present in the second are returned. All elements present in one sequence or the other but not in both are returned. Thus, the set methods can take a set or any sequence type as an argument.
Government is actually the worst failure of civilized man.
There has never been a really good one, and even those that are most tolerable are arbitrary, cruel, grasping and unintelligent.