Digit Sum By Recursion

Complete digit_sum(n: int) -> int so it returns the sum of the digits of a non-negative integer by recursion. The base case is written: a number below 10 is a single digit and is its own digit sum. Add the recursive case, which returns the last digit (the remainder operator % with 10) plus the digit sum of the number with that digit removed (floor division // by 10). Do NOT write a main block or any top-level test code; the tests construct the calls. Input: one integer n, no prompt, which the tests read and pass to your function before printing the value it returns.