Function sum

Python/5 recusrion problems.py:48–53

(n)

# 4..TO FIND THE SUM OF ALL DIGITS IN THE GIVEN NUMBER

def sum(n):
    assert n>=0 and int(n)==n , "only positive integers"
    if n==0:
        return 0
    else:
        return int(n%10) + sum(int(n//10))

print(sum(11))