Question: 
Write a function to compute the sum of digits of each number of a given list.


Model's Code:
def sum_of_digits(numbers):
    def digit_sum(n):
        return sum(int(d) for d in str(abs(n)) if d.isdigit())
    
    total = 0
    for num in numbers:
        if isinstance(num, list):
            total += sum_of_digits(num)
        else:
            total += digit_sum(num)
    return total



Sample Correct Code:
def sum_of_digits(nums):
    return sum(int(el) for n in nums for el in str(n) if el.isdigit())


Asserts:
assert sum_of_digits([10,2,56])==14
assert sum_of_digits([[10,20,4,5,'b',70,'a']])==19
assert sum_of_digits([10,20,-4,5,-70])==19


Tests:
Test 1 of 3: PASS
Test 2 of 3: FAIL: TypeError("bad operand type for abs(): 'str'")

Test 398 of 974: 287/398 (72.11055276381909%): failed