That the bonds issued under the provisions of the next two preceding sections shall be sold in the manner provided by law. No part of the proceeds thereof shall be used for any other purpose than the payment of the costs incurred in constructing the improvements for which they were issued. Legal, engineering and other special services required in planning and constructing the improvement shall be considered as part of the cost of the improvements and may be paid from the proceeds of the bond sale.
K.S.A. 19-2772