def METHOD_NAME(a: Tuple[int, int], b: Tuple[int, int]) -> Tuple[int, int]:
    "returns (sec, nsec) -- sec may be negative, nsec is always positive"
    sec_diff = a[0] - b[0]
    nsec_diff = a[1] - b[1]
    nsec = nsec_diff % SEC_TO_NSEC
    nsec_excess = nsec_diff - nsec
    assert nsec_excess % SEC_TO_NSEC == 0, f"{a} - {b}"
    return (sec_diff + nsec_excess // SEC_TO_NSEC, nsec)