Arithmetic bitwise right shift

def sar(computation: BaseComputation) -> None:
    """
    Arithmetic bitwise right shift
    """
    shift_length, value = computation.stack_pop(num_items=2, type_hint=constants.UINT256)
    value = unsigned_to_signed(value)

    if shift_length >= 256:
        result = 0 if value >= 0 else constants.UINT_255_NEGATIVE_ONE
    else:
        result = (value >> shift_length) & constants.UINT_256_MAX

    computation.stack_push(result)