All debts, contracts and obligations heretofore made or incurred by or in favor of any city or town incident to the conversion of overhead electric and communication facilities to underground facilities and all bonds, warrants, or other obligations issued by any such city or town, or by any local improvement district created to effect such conversion and any and all assessments heretofore levied in any such local improvement district, and all other things and proceedings relating thereto are hereby declared to be legal and valid and of full force and effect from the date thereof.
RCW 35.96.070