50 ILCS 440/1

The validity of any bond, interest coupon or certificate of indebtedness legally authorized and issued by any county, city, village, incorporated town, township, school district, park district, road district, drainage district, sanitary district, authority or any other municipal corporation or political subdivision in the State of Illinois shall remain unimpaired although one or more of the officers executing such bond, interest coupon or certificate of indebtedness shall have ceased to be such officer or officers before delivery thereof to the purchaser.