Whenever in any proceeding instituted by any city in this state for the purchasing, taking or damaging of property for public purposes, provision is made in the judgment in said proceeding for the payment in annual installments of assessments of benefits against property for the purchasing, taking or damaging of property for public purposes, the time within which execution may be issued on the judgment assessing any such benefits shall not expire until two years after the date upon which the last installment shall be due, and default in the payment of any prior installment shall not shorten the time within which such execution may be issued.