No tax is imposed by this chapter with respect to any transaction in interstate commerce or otherwise to the extent to which such business may not, under the constitution and statutes of the United States, be made subject to taxation by this state or any political subdivision thereof; nor shall any persons engaged in the business of distributing, supplying, furnishing or selling gas or electricity, or engaged in the business of transmitting messages be subject to taxation by this state or any political subdivision thereof; nor shall any persons engaged in the business of distributing, supplying, furnishing or selling gas or electricity, or engaged in the business of transmitting messages be subject to taxation under the provisions of this chapter for such transactions as are or may become subject to taxation under the provisions of the "municipal retailers' occupation tax act" authorized by statute and this code. (Ord. 99-05, 6-14-1999)