Repetitive Addition Of Digits using Python3

Repetitive Addition Of Digits
I solved this problem geeksforgeeks, where we need to add the given digit till the output come in single digit.

Question: https://practice.geeksforgeeks.org/problems/repetitive-addition-of-digits2221/1#

Solution:

class Solution:

def SumOfDigit(self,N):

sum_digit = 0

for digit in str(N):

sum_digit += int(digit)

return sum_digit

def singleDigit(self, N):

#code here

if N < 10:

return N

return self.singleDigit(self.SumOfDigit(N))

Above code pass all test scenario.