AN ACT TO ALLOW FOR THE PURCHASE OF UP TO FOUR YEARS' CREDITABLE SERVICE IN THE TEACHERS' AND STATE EMPLOYEES' RETIREMENT SYSTEM OR THE LOCAL GOVERNMENT EMPLOYEES' RETIREMENT SYSTEM AT FULL COST BY LAW ENFORCEMENT OFFICERS HOLDING AN ADVANCED LAW ENFORCEMENT CERTIFICATE ISSUED BY THE NORTH CAROLINA CRIMINAL JUSTICE EDUCATION AND TRAINING STANDARDS COMMISSION OR THE NORTH CAROLINA SHERIFFS' EDUCATION AND TRAINING STANDARDS COMMISSION.