OPINION — AG — WHERE THE CHARTER OF A HOME RULE CITY PROVIDES THAT ALL CITY COUNCIL MEETINGS SHALL BE OPEN TO THE PUBLIC, THE COUNCIL MAY NOT GO INTO EXECUTIVE SESSION UNDER 25 O.S. 1977 Supp., 307 [25-307] OF THE STATE OPEN MEETING ACT, UNLESS THE CITY CHARTER IS AMENDED TO ALLOW SUCH SESSIONS. (MUNICIPALITY) CITE: 11 O.S. 1977 Supp., 13-111 [11-13-111] (MARY BRYCE LEADER)