> If you've used Java or Python, you'll probably be familiar with the idea that some types of data behave differently from others when you assign them from one variable to another. If you write an assignment such as ‘a = b’ where a and b are integers, then you get two independent copies of the same integer: after the assignment, modifying a does not also cause b to change its value.

This is incorrect when it comes to Python. a and b will be two different names for the same integer object, which is stored in a single memory location. The difference is that Python guarantees that integers are immutable.