Book errata（on page 81)

[pxtalk]

x = [1, 2, 3]
>>> y = [2, 4]
x is not y

should be：

x = [1, 2, 3]
>>> y = [2, 1]
x is not y

[georgiosdoumas]

The example as appears on the book is correct. There is no need for editing anything.
Here is the example on a more elaborate form as I did it on my IDLE:

x=[1,2,3]
y=[2,4]
x is not y
True
del x[2]
x
[1, 2]
y[1]=1
y
[2, 1]
y.reverse()
y
[1, 2]
x==y
True
x is y
False
Please delete this issue, or mark it as solved.