tail package:dlist

tail xs is a list of the elements in xs excluding the first element. If xs is empty, an error is raised. <math>(length (toList xs)). tail obeys the law:
tail xs = tail (toList xs)
tail xs is a DList of the elements in xs excluding the first element. <math>(1). tail obeys the law:
toList (tail xs) = tail (toNonEmpty xs)