append(@rest list1, ..., obj)
Return a new list consisting of the elements of the first list followed by the elements of the second list, the elements of the third list, and so on. The new list is made from new pairs for all arguments but the last; the last (which need not be a list) is merely placed at the end of the new structure. Raise an error if all but the last argument are not lists.
append()
// []
append([1, 2, 3], [4, 5, 6])
// [1, 2, 3, 4, 5, 6]
append([1, 2, 3], [4, 5, 6], 7)
// 1:2:3:4:5:6:7