iter.py

class BetterIter(object):

    def __init__(self, items):
        self.items = items[:]
        self._max_index = len(self.items) - 1
        self._index = 0

    def __getitem__(self, key):
        try:
            return self.items[key]
        except IndexError:
            return None

    @property
    def current_item(self):
        return self[self._index]

    def next(self):
        self._index += 1
        if self._index > self._max_index:
            self._index = 0
        return self.current_item

    def prev(self):
        self._index -= 1
        if self._index < 0:
            self._index = self._max_index
        return self.current_item