import itertools
import functools
def powerlist(l):

    indexes = {}
    for i, e in enumerate(l):
        indexes[e] = i

    combos = []
    for i in range(1, len(l) + 1):
        combos = combos + list(list(tup) for tup in itertools.combinations(l, i))

    def compare(item1, item2):
        if indexes[item1[-1]] < indexes[item2[-1]]:
            return -1
        elif indexes[item1[-1]] > indexes[item2[-1]]:
            return 1
        else:
            if len(item1) < len(item2):
                return -1
            elif len(item1) > len(item2):
                return 1
            else:
                for i in range(len(item1) - 1, -1, -1):
                    if indexes[item1[i]] < indexes[item2[i]]:
                        return -1
                    elif indexes[item1[i]] > indexes[item2[i]]:
                        return 1
                return 0

    combos.sort(key=functools.cmp_to_key(compare))
    combos = [[]] + combos
    return combos