Question $5($hw$4\_$q$5.$py$)$: The Great A$-$B Swap$-$a$-$Thon

Write a Python program that takes an integer, max$\_$num as input and creates a pattern using nested loops.

The pattern will be a combination of letters $\text{'}$ A $\text{'}$ and $\text{'}$ B $\text{'}$ in a specific arrangement.

Here's how the pattern should be generated:

$1.$ Start with a string containing only the letter $\text{'}$ A $\text{'}.$

$2.$ For each iteration from $1$ to max$\_$num, you will create a new string by following these rules:

$-$ Start with the previous string.

$-$ Replace all $\text{'}$A$\text{'}$ characters with $\text{'}$B$\text{'}$ and all $\text{'}$B$\text{'}$ characters with $\text{'}$A$\text{'}$

$-$ Append the new string to the previous string.

For example, if the user enters $4$ as max$\_$num, the pattern would be generated as follows:

$-$ Iteration $1$: A

$-$ Iteration $2$: AB

$-$ Iteration $3$: ABBA

$-$ Iteration $4$: ABBABAAB

Make your program print the patterns during all the max$\_$num iterations.

Here is a sample execution:

$```$

Enter a positive integer: $4$

Iteration $1$: A

Iteration $2$: AB

Iteration $3$: ABBA

Iteration $4$: ABBABAAB

$```$