submission for codewars.com digital root

digital_root.py

def digital_root(n):
    """ digital_root - recursively figure out the digital root of a number"""
    s = 0 # s -> running sum
    while n > 0:
        # take each digit from the number by running mod 10 (ones position in base 10 number)
        s += int(n%10)
        # reduce the number by a factor of 10 to remove the ones position
        n = int(n/10)
    if s >= 10: 
        # if the num is greater than or equal to 10 recursively call self
        return digital_root(s)
    # return the sum
    return s