The deductions, which are to be made before the partition of a succession, consist:
1. Of the sums due to one or more of the heirs for a debt due them by the deceased, or advance [advances] made to the succession, or expenses on its effects, according to the account settled among the heirs;
2. Of the amount owing to the heirs to whom a collation is due, when the collation is made by taking less, in order that the heirs may receive a portion equal to the amount of the collation which is due;
3. Of the privileged debts due or paid on account of the succession, which have been incurred since the death of the deceased, or in order to effect the partition.