def METHOD_NAME(self, treemodel, iter1, iter2, user_data):
    try:
        p1 = int(treemodel.get_value(iter1, 1))
        p2 = int(treemodel.get_value(iter1, 1))
        if p1 > p2:
            return 1
        if p1 == p2:
            return 0
        return -1
    except:
        return 0