def sequential_search(target, lyst):
    """
    in()
    顺序搜索
    Returns the position of the target item if found, or -1 otherwise.
    :param target:
    :param lyst:
    :return:
    """
    position = 0
    while position < len(lyst):
        if target == lyst[position]:
            return position
        position += 1
    return -1