(a) On such terms as is deemed advisable and as may meet the approval of the board or court before which the proceedings are had, the taxing district may assume and pay any overdue special improvement taxes of any lands embraced in the subsidiary district from the fund produced by the sale of certificates of indebtedness or of refunding bonds of the taxing district.
(b) The taxes so paid, including penalties, cost of redemption, or any other necessary cost incurred, must be allocated to each tract of land properly chargeable with it, and proper proceedings must be had by which the taxing district may be given sufficient lien or may become subrogated to all rights of existing lienors or pledgees to the end that the taxing district may have a first lien on the lands whose obligation it has assumed for all special taxes paid by it.