If the obligation does not fix a period, but from its nature and the circumstances it can be inferred that a period was intended, the courts may fix the duration thereof.
The courts shall also fix the duration of the period when it depends upon the will of the debtor.
In every case, the courts shall determine such period as may under the circumstances have been probably contemplated by the parties. Once fixed by the courts, the period cannot be changed by them. (1128a)