Where is the optimal place to insert a print statement in the for loop of the following code to see how the list is being built and help debug the code?

$1$ multiples $=[]$

$2$

$3$ for outer in range$(1,3)$:

$4$

$5$ multiples.append$([])$

$6$

$7$ for inner in range$(1,3)$:

$8$

$9$ multiples$[$outer$-1].$append$($inner$)$

$10$

line $6$

line $4$

line $8$

line $10$