def total(numbers)sum_so_far for number in numberssum_so_far +number return sum_so_far total py equivalent def total(numbers)sum_so_far for index in range(len(numbers))sum_so_far +numbers[indexreturn sum_so_far total py let' quickly remind ourselves about how we can uses indices for lists rather than values from lists directly we found this particularly useful when we were traversing more than one list at once