How to sum, without using + or - in Python

sum.py

def sum_bits(larger, smaller):
    """ Sum but using bits, only positive numbers"""

    top_down_sum = larger ^ smaller
    carry = (larger & smaller) << 1
    if carry > 0:
        return sum_bits(top_down_sum, carry)
    return top_down_sum

def sub_bits(larger, smaller):
    """Subtraction but using bits, only positive numbers"""

    top_down= larger ^ smaller
    borrow = ((~larger) & smaller) << 1

    while borrow > 0:
        return sub_bits(top_down, borrow)
    return top_down


def sum(larger_number:int, smaller_number:int):
    """ Sum function, in O(1) time and space, using bitwise operators
    Can sum positive with negative and any combination
    """

    abs_larger = abs(larger_number)
    abs_smaller = abs(smaller_number)

    if abs_larger < abs_smaller:
        return sum(smaller_number, larger_number)

    to_plus = larger_number* smaller_number >= 0
    sign = 1 if larger_number > 0 else -1

    if to_plus:
        return sum_bits(abs_larger, abs_smaller) * sign
    else:
        return sub_bits(abs_larger, abs_smaller) * sign

print(sum(5, 5))
# >> 10