The purpose of this chapter is to regulate trade practices in the business of insurance in accordance with the intent of congress as expressed in Public Law 79-15 (the McCarran-Ferguson Act, 15 U.S.C. 1011 through 1015), which was approved March 9, 1945, by defining or providing for determination of all such practices in this state which constitute unfair methods of competition or unfair or deceptive acts or practices and by prohibiting the trade practices so defined or determined.