列表理解和list.insert（）问题

Question

此代码：

    total = 12
    for i in range(1, total+1, 3):
        x = [x for x in range(i, i+3)]
        print(x)
        print(x.insert(0, 0))

在Python 3.7上打印出以下内容：

[1, 2, 3]
None
[4, 5, 6]
None
[7, 8, 9]
None
[10, 11, 12]
None

我希望它打印出来：

[1, 2, 3]
[0, 1, 2, 3]
[4, 5, 6]
[0, 4, 5, 6]
[7, 8, 9]
[0, 7, 8, 9]
[10, 11, 12]
[0, 10, 11, 12]

我在做什么错了？