Assume that for this problem Python's * operator does not exist. Addition is all you have.
Write the function mult_iter(a, b) that returns the product of a (any integer) and b (a non-negative integer), computed iteratively — a loop plus whatever state variables you need. You may not use *, **, pow, or sum. Your function must give the right answer when b is 0.
mult_iter(5, 4) # 20 mult_iter(7, 1) # 7 mult_iter(3, 0) # 0 mult_iter(-6, 3) # -18