def __add__(self, lst):
    new_list = Link(self.first)
new_link = new_list
current = self
while current.rest != self.empty:
    new_link.rest = Link(current.first)
new_link = new_link.rest
current = current.rest
current = lst
while current != self.empty:
    new_link.rest = Link(current.first)
new_link = new_link.rest
current = current.rest
return new_list
Combining linked lists iteratively