Function that takes a positive integer n as input and returns the sum of all that number's digits. For example: digit_sum(1234) should return 10 which is 1 + 2 + 3 + 4.

digit_sum.py

def digit_sum(n):
    total = 0
    numberStringfied = str(n)
    listNumbers = list(numberStringfied)
    for n in listNumbers:
        total += int(n)
        
    return total