Parish governing authorities, school boards and municipal corporations, the city of New Orleans excepted, may dedicate, appropriate and pledge not more than two mills of the taxes respectively authorized to them for a period not exceeding twenty-five years, for the payment of any indebtedness, matured or unmatured, exclusive of bonded indebtedness, lawfully incurred or contracted prior to July 1, 1942, and they may issue certificates of indebtedness therefor.
Certificates of indebtedness may be issued also for the payment of all expenses incurred or contracted in the issuance of the certificates of indebtedness, and if the expenses are so provided for, certificates covering them shall be included in the issue herein provided for.