The Council, subject to the applicable provisions of State law, may borrow money in anticipation of collecting special assessments made for the purpose of defraying the cost of any public improvement, or issue bonds in anticipation of collecting any combination of special assessments. The special assessment bonds may be solely an obligation of the related special assessment district or districts or may be both an obligation of the special assessment district or districts and a general obligation of the City. All collections on each special assessment roll, or combination of rolls, shall be set apart in a separate fund for the payment of the principal and interest of the bonds issued in anticipation of the payment of such special assessments, and shall be used for no other purpose.