A reversible Pythonic LinkedList class

reversible_linked_list.py

class LinkedList:
    def __init__(self, collection):
        try:
            iterator = iter(collection)
            head = next(iterator)
            self._value = head
            tail = LinkedList(iterator)
            self._tail = tail
            self._len = tail._len + 1
        except StopIteration:
            self._len = 0

    def __len__(self):
        return self._len

    def __iter__(self):
        if self:
            yield self._value
            yield from self._tail.__iter__()

    def __reversed__(self):
        if self:
            yield from self._tail.__reversed__()
            yield self._value

    def __repr__(self):
        return 'LinkedList(%s)' % list(self)


#### alternative, tuple-based approach ####
def linked_list(collection):
    try:
        iterator = iter(collection)
        head = next(iterator)
        return head, linked_list(iterator)
    except StopIteration:
        return None


def reversed_ll(ll):
    if not ll:
        return ll
    prev_pair = None
    value, next_pair = ll
    while next_pair:
        prev_pair = (value, prev_pair)
        value, next_pair = next_pair
    return prev_pair