docs: def union(self, *args):
          """
          Produce an array that contains the union: each distinct element
          from all of the passed-in arrays.
          """
          # setobj = set(self.obj)
          # for i, v in enumerate(args):
          #     setobj = setobj + set(args[i])
          # return self._wrap(self._clean._toOriginal(setobj))
          args = list(args)
          args.insert(0, self.obj)
          return self._wrap(_.uniq(self._flatten(args, True, [])))