[Python] Why does Online Python Tutor present this immutable integer as two different integers...

In Fluent Python, By Luciano Ramalho, Chapter 8, Copies Are Shallow by Default, there is an example:

>>> listOne = [3, [55, 44], (7, 8, 9)]
>>> listTwo = list(listOne)
>>> listTwo
[3, [55, 44], (7, 8, 9)]
>>> listTwo == listOne
True
>>> listTwo is listOne
False


The author suggests that we should run through this code using Online Python Tutor to see what is happening step by step.

I executed the first two lines using Online Python Tutor, and this is the screen shot I got:



What confuses me is:

All three elements from the each list, the immutable integer, the list and the tuple are actually the same, e.g.

listOne[0] is listTwo[0] #True
listOne[1] is listTwo[1] #True
listOne[2] is listTwo[2] #True


So why the graph shows two separate 3s at the beginning of their respective list?

Continue reading...