Question: 
Write a function to get the sum of a non-negative integer.


Model's Code:
def sum_digits(n):
    return sum(int(digit) for digit in str(n))



Sample Correct Code:
def sum_digits(n):
  if n == 0:
    return 0
  else:
    return n % 10 + sum_digits(int(n / 10))


Asserts:
assert sum_digits(345)==12
assert sum_digits(12)==3
assert sum_digits(97)==16


Tests:
Test 1 of 3: PASS
Test 2 of 3: PASS
Test 3 of 3: PASS

Test 566 of 974: 420/566 (74.20494699646643%): success