编写一个python程序 打印消息“The first three items in the list are”,再使用切片来打印列表的前三个元素，中间三个元素，末尾三个元素。

lst = [1, 2, 3, 4, 5, 6, 7, 8, 9]

print("The first three items in the list are:") print(lst[:3])

print("The middle three items in the list are:") print(lst[3:6])

print("The last three items in the list are:") print(lst[-3:])