def difference(set1, set2):
    """
    take two lists
    return the differences

    NOTE THAT ORDER MATTERS!
    if 1 is a superset of 2, there will be a difference
    but if 2 is a superset of 1, there won't be a difference

    i.e.
    larger set first!
    larger = set1, smaller = set2
    """
    diff = []
    for i in set1:
        if not i in set2:
            diff.append(i)
    return diff