(1) Either of the contractual parties may, in the contract of inheritance, unilaterally make any disposition that may be made by will.
(2) For a disposition of this kind the same applies as if it had been made by will. The disposition also may be cancelled in a contract by which a contractual disposition is cancelled.
(3) If the contract of inheritance is cancelled by the exercise of the right of revocation or by contract, the disposition ceases to be effective, unless it is to be assumed that the testator intended otherwise.