def abs_of_difference(num1: int, num2: int) -> int:
    """
    precondition: parameters must be numbers
    calculate difference between num1 and num2 and compute absolute value of the result

    >>> abs_of_difference(-4,5)
    9
    >>> abs_of_difference(1,-3)
    4
    >>> abs_of_difference(2,2)
    0
    """
    return abs(num1 - num2)